Session 07 - Image and Video Essentials / User Experience and Design

Topics

1. Image Essentials
2. JPEG
3. GIF
4. PNG
5. WebP - Web Picture
6. SVG
7. Comparison of Image Formats
8. Maintain aspect ratio for images
9. Working with Images
10. Video
11. Elements of User Experience
12. Strategy
13. Scope
14. Structure
15. Skeleton
16. Surface

Session 07 - Image and Video Essentials / User Experience and Design, slide1
Image Essentials, slide2
Images and the Web, slide3
Images and HTML - , slide4
Images and HTML - , slide5
Responsive Images, slide6
and attributes, slide7
and , slide8
and examples, slide9
example for multi-column image layout, slide10
element, slide11
Graphics Formats for the Web, slide12
Does it matter? — image. or image. or image. or image. , slide13
Graphics: Vector and Bitmap, slide14
Colors, slide15
Color Depth, slide16
Indexed Color Systems, slide17
Bitmap images: Size and Quality, slide18
Images and Sizes, slide19
Graphics Formats for the Web, slide20
JPEG, slide21
JPEG Compression, slide22
JPEG Compression Artifacts, slide23
GIF, slide24
Palettes, slide25
Palettes: Exact, Adaptive, Web 216, slide26
Adaptive Palette: Shift and Dither, slide27
GIF Images and Bit Depth: Color Shift, slide28
GIF Images and Bit Depth: Dither, slide29
Compression for Indexed GIF, slide30
Compression and Dithering, slide31
Transparency, slide32
GIF Animation, slide33
PNG, slide34
Compression for Indexed PNG, slide35
Compression and Dithering, slide36
Transparency, slide37
WebP - Web Picture, slide38
SVG, slide39
Basic SVG Shapes, slide40
SVG - Increasing Importance in the Future, slide41
Colorado State Flag, slide42
Harvard Division of Continuing Education Shield, slide43
Icons, slide44
SVG Example - Molecule Viewer, slide45
Comparison of Image Formats, slide46
Cartoon Art, slide47
Wordmarks, slide48
Maintain aspect ratio for images, slide49
Working with Images, slide50
Imgix, slide51
Finding Images to Use, slide52
Placeholder Images, slide53
Start with Original PSD/AI/etc. or High Resolution PNG or JPEG, slide54
Video, slide55
What's Changed since 2001, slide56
Video vs Images, slide57
Download vs Stream, slide58
HTTP Live/Dynamic Streaming, slide59
Example Video, slide60
Video Quality, slide61
Video Hosting, slide62
Elements of User Experience, slide63
5 Planes in More Detail, slide64
Design and UX Resources, slide65
Strategy, slide66
Who are our Users?, slide67
What Audiences can be identified?, slide68
Audience(s), slide69
Audiences for an Academic Department, slide70
Scope, slide71
Content, slide72
Think About the User, slide73
Structure, slide74
Structuring Content, slide75
Organize, slide76
Structural Models, slide77
Hierarchical, slide78
Biological, slide79
Too deep or too shallow?, slide80
Sequential, slide81
Organic, slide82
Site Architecture, slide83
Label, slide84
Labels - Are there conventions?, slide85
Skeleton, slide86
Page Components, slide87
Wireframes and Sketches - "Low" to "High" Fidelity, slide88
First Low-fidelity Skeleton for a Project, slide89
Navigation Systems, slide90
Some navigation systems illustrated, slide91
Surface, slide92
Non-Designer's Design Book, slide93
Non-Designer's Design Book, slide94
Colors, slide95
Home Page -- Don't Make Me Think (Steven Krug), slide96
Don't make me think, slide97

Presentation contains 97 slides

Image Essentials

• Use an appropriate format (JPEG or WebP for photographs; PNG or WebP for wordmarks, illustrations; SVG sometimes)
• If adjusting an image, start with the highest resolution, lowest compression available!
  • Set an appropriate image dimension (or resolution)
  • Set an appropriate compression
  • Preserve the aspect ratio

Images and the Web

• Content
• Design

Images and Markup

Two ways of including images:

1. Markup: img element

   <img src="images/widener-library.png"
    alt="Widener Library" >

2. CSS: background-image property

   header {
      background-image: url(images/harvard-yard.jpg);
      background-repeat: no-repeat;
      background-size: cover;
      }

Images and HTML - figure

Figure element is used to mainly to associate a caption with an image.

<figure>
    <img src="images/thiomargarita-magnifica.jpg"
    alt="Thiomargarita magnifica" />
    <figcaption>
    The filamentous <i>Thiomargarita magnifica</i>
    cells have more complex internal organization
    than do typical bacteria.<br/>
    Credit: Olivier Gros/Lawrence Berkeley National Laboratory
    </figcaption>
  </figure>

• <picture>: The Picture Element | MDN
• Figure Example

Images and HTML - picture

Picture element can be used to provide conditional image sources for content, with a fallback

<picture>
  		<source srcset="landscape.jpg" media="(min-width: 800px)">
  		<source srcset="extrawide.jpg" media="(min-width: 1200px)">
  		<img src="portrait.png"
  			 alt="placeholder image" />
  </picture>

• <picture>: The Picture Element | MDN

Responsive Images

Two main use cases:

• Deliver same image but with different properties, e.g. resolution or format
  ☞ Use img element with srcset and sizes attribute
• Deliver different images in different contexts
  ☞ Use picture element

srcset and sizes attributes

• Lists different resolutions/dimensions
• Use with img element

srcset and sizes

srcset lists image options
sizes relates width of browser to width of image to select

<img src="images/gnp.jpg"
  	alt="Glacier National Park"

  	srcset="images/gnp-500.jpg 500w,
  	images/gnp-600.jpg 600w,
  	images/gnp-900.jpg 900w,
  	images/gnp-1200.jpg 1200w,
  	images/gnp-1500.jpg 1500w"

  	sizes="(min-width: 550px) 90vw,
  	       500w" />

srcset and sizes examples

• Demo of srcset with placeholder images
• Demo of srcset with imgix delivery

sizes example for multi-column image layout

<img src="images/earth.t.jpg" alt=""
  	srcset="images/earth/earth-200.jpg 200w,
  	images/earth/earth-250.jpg 250w,
  	images/earth/earth-300.jpg 300w,
  	images/earth/earth-350.jpg 350w,
  	images/earth/earth-400.jpg 400w,
  	images/earth/earth-450.jpg 450w,
  	images/earth/earth-500.jpg 500w,
  	images/earth/earth-550.jpg 550w,
  	images/earth/earth-600.jpg 600w,
  	images/earth/earth-650.jpg 650w,
  	images/earth/earth-700.jpg 700w,
  	images/earth/earth-750.jpg 750w,
  	images/earth/earth-800.jpg 800w,
  	images/earth/earth-900.jpg 900w,
  	images/earth/earth-1000.jpg 1000w"
  	sizes="(max-width: 750px) 100vw,
  		   (max-width: 1090px) 50vw,
  		   (max-width: 1425px) 33vw,
  		   (min-width: 1426px) 25vw"
  	/>

picture element

• Lists alternative “source” elements and conditions
• Different orientations (e.g. landscape or portrait) as well as image format types

picture

<picture>
  	<source srcset="images/harvard-yard-landscape.jpg"
  			media="(min-width: 800px)">
  	<img src="images/harvard-yard-portrait.jpg" alt="Harvard Yard" />
  </picture>

• Demo of picture with different aspect ratios
• Demo of picture with different image formats

Graphics Formats for the Web

PNG

Portable Network Graphic

.png

JPEG

Joint Photographic Experts Group

.jpeg or .jpg

WebP

Web Picture

WebP is a modern image format that provides superior lossless and lossy compression for images on the web. Using WebP, webmasters and web developers can create smaller, richer images that make the web faster.

.webp

SVG

Scalable Vector Graphic

A vector based format that is becoming more important for the web and uses an XML-based format.

.svg and .svgz

GIF

Graphics Interchange Format

GIF goes back to the days of CompuServe in 1987 (remember that?!)

.gif

Other formats

Image formats you might encounter, but aren't super-relevant for the web:

• HEIC (Apple Live Photos)
• TIFF
• JPEG 2000 (JP2)
• RAW
• BMP
• ICO

Does it matter? — image.jpg or image.JPG or image.jpeg or image.JPEG

JPG or jpg

• Yes. If your filename is "beach.JPG" then you need to reference it as "beach.JPG" — having "beach.jpg" in the URL won't work!

  The following work for a file named "beach.jpg":

  <img src="images/beach.jpg" alt="Sandy beach and ocean on Cape Code" />

  main div.hero {
    background-image: url(../images/beach.jpg);
    background-size: cover;
  }

  The following work for a file named "beach.JPG":

  <img src="images/beach.JPG" alt="Sandy beach and ocean on Cape Code" />

  main div.hero {
    background-image: url(../images/beach.JPG);
    background-size: cover;
  }

• No. From an "image" standpoint, .jpg or .JPG or .jpeg or .JPEG doesn't matter. As long as the case of your filenames match the case in your URL references you'll be fine.

jpeg or jpg

• Yes. See note above about case and names matching between references in HTML markup and file names.
• No. Media types can be mapped to multiple file extensions, so generally either picture.jpg or picture.jpeg filenames are fine.
  And for JPEG images, the media type (also known as MIME type) is "image/jpeg"

Graphics: Vector and Bitmap

Bitmap	Vector
Original image (PNG):	Original image (SVG):
Magnified (16x)	Magnified (16x)
Bitmap formats: PNG, JPEG, GIF	Vector formats: SVG

Colors

RGB Color Space

Color Depth

• RGB color is a 24-bit system (16 million colors)
• 8 bits (256 colors) for each channel (red, green, blue).

  2⁸x2⁸x2⁸ = 2^{(8 + 8 + 8)} = 2²⁴x = 16,777,216

RGB

• Three channels specified with decimal values (each channel 0 to 255):
  rgb(50, 150, 0)
• Three channels specified with hexadecimal values (each channel 00 to ff):
  #a51c30
• Three channels specified with percentage values (each channel 0% to 100%):
  rgb(50%, 10%, 75%)

Indexed Color Systems

An 8-bit indexed image has a palette of up to 256 colors that the image can contain. Color information is not stored for each pixel, but rather just a reference to which color in the palette.

Palettes

• Exact (if 256 or fewer colors)
• Adaptive (weighted based upon colors in document)

But what happens to the other colors?

If you take a photo that is saved in an RGB system (millions of colors) and then convert it to an indexed system with 256 colors, what happens?

• dither
• color-shift

Bitmap images: Size and Quality

Factors that can contribute to image size:

• Dimension
• Format
• Compression

Images and Sizes

Take an 800x600 px image:
800 × 600 = 480,000 pixels total

Assuming no compression:

• For RGB
  • 8 + 8 + 8 = 24 bits per pixel
  • (480,000 px × 24 bits/px) ÷ (8 bits / byte) = 15,360,000 bytes
  • 1,440,000 bytes = 1,406 kb = 1.37 Mb (divide by 1024 for each step)
• For 8-bit Indexed (256 colors)
  • 8 bits per pixel to reference the palette
    (480,000 px × 8 bits/px) ÷ (8 bits / byte) = 480,000 bytes
  • 256 colors in palette ÷ 256 bits per color = 65,536 bits = 8192 bytes
  • 480,000 + 8,192 = 488,192 bytes = 477 kb = 0.47 Mb

Either way, this isn't good.
The page weight in September 2022 was around 2.2 Mb desktop and 2 Mb mobile

But, of course, there is "compression"

• Compression algorithms that are part of image formats
• Compression can be "lossy" or "lossless"

Graphics Formats for the Web

Property	GIF Graphics Interchange Format	JPEG Joint Photographic Experts Group	PNG Portable Network Graphic		SVG Scalable Vector Graphics	WebP
Color System	8 bit indexed (256 colors)	RGB (24 bit; millions of colors)	8 bit indexed (256 colors) RGB (24 bit; millions of colors)		RGB	RGB
Compression	Lossless Compression (LZW; horizontal repeating units)	"Lossy" Compression (compression optimized for gradual color changes)	Lossless Compression		Lossless Compression	Lossless and Lossy
Other Features	.gif file extension Transparency Animation	.jpg and .jpeg file extensions No Transparency No Animation	.png file extension Transparency		.svg file extension Vector-based Transparency XML format	25% smaller than equivalent PNGs and JPEGs. Supports transparency
Typical Uses	Illustrations (logos, icons) Animated banners and icons Images with small dimension	Photographs	Any		Illustrations Graphs, Charts, Maps - 'plain' and 'interactive'	Any
Property	GIF Graphics Interchange Format	JPEG Joint Photographic Experts Group	PNG Portable Network Graphic		SVG Scalable Vector Graphics	WebP
Photograph 250 × 188 px	29.3 kb	16.8 kb	25.8 kb (indexed, 8-bit)	81.9 kb (RGB, 24-bit)	N/A	9.6 kb
Illustration 148 × 179 px	1.47 kb	6.12 kb	1.02 kb (indexed, 8-bit)	1.89 kb (RGB, 24-bit)	0.575 kb (compressed, 1.7 kb uncompressed; RGB, 24-bit)	0.724 kb

JPEG

Joint Photographic Experts Group

Property	JPEG Joint Photographic Experts Group
Color System	RGB (24 bit; millions of colors)
Compression	"Lossy" Compression (compression optimized for gradual color changes)
Other Features	.jpg and .jpeg file extensions No Transparency No Animation
Typical Uses	Photographs
Property	JPEG Joint Photographic Experts Group
Photograph 250 × 188 px	16.8 kb
Illustration 148 × 179 px	6.12 kb

JPEG Compression

The amount of compression (quality of image) for a JPEG image can be chosen (from a scale of 0 to 100). The image quality is inversely related to the amount of compression since the compression algorithm is "lossy".

Properties	Image
Quality: 80 34.1 kb
Quality: 70 26.0 kb
Quality: 60 22.4 kb
Quality: 50 17.0 kb
Quality: 40 14.3 kb
Quality: 30 6.97 kb
Quality: 20 4.80 kb
Quality: 10 3.75 kb
Quality: 1 3.21 kb

JPEG Compression Artifacts

Typically first appears at boundaries in images. Portions of image can also become "blocky".

Schlieren at boundaries:

Blockyness

GIF

Property	GIF Graphics Interchange Format
Color System	8 bit indexed (256 colors)
Compression	Lossless Compression (LZW; horizontal repeating units)
Other Features	.gif file extension Transparency Animation
Typical Uses	Illustrations (logos, icons) Animated banners and icons Images with small dimension
Property	GIF Graphics Interchange Format
Photograph 250 × 188 px	29.3 kb
Illustration 148 × 179 px	1.47 kb

Palettes

An 8-bit indexed image has a palette of up to 256 colors that the image can contain. Color information is not stored for each pixel, but rather just a reference to which color in the palette.

Palettes

• Exact (if 256 or fewer colors)
• Adaptive (weighted based upon colors in document)

Not relevant today, but in the web's history:

• Web Palette (216 Web Safe Colors)
• System
  • Windows
  • Macintosh

Palettes: Exact, Adaptive, Web 216

Exact Palette
Image	Palette
Adaptive Palette
Image	Palette
Web 216 Palette
Image	Palette

Adaptive Palette: Shift and Dither

Color Shift

Image (16 colors; Color Shift)	Zoom

Dither

Image (16 colors; Dither)	Zoom

GIF Images and Bit Depth: Color Shift

Properties	Image	Palette (adaptive)
8 bit 256 colors 46.3 kb
7 bit 128 colors 36.2 kb
6 bit 64 colors 28.9 kb
5 bit 32 colors 21.9 kb
4 bit 16 colors 16.5 kb
3 bit 8 colors 10.9 kb
2 bit 4 colors 7.31 kb
1 bit 2 colors 2.84 kb

GIF Images and Bit Depth: Dither

Properties	Image	Palette (adaptive)
8 bit 256 colors 64.9 kb
7 bit 128 colors 52.3 kb
6 bit 64 colors 43.4 kb
5 bit 32 colors 34.7 kb
4 bit 16 colors 26.7 kb
3 bit 8 colors 18.6 kb
2 bit 4 colors 14.2 kb
1 bit 2 colors 5.86 kb

Compression for Indexed GIF

GIF LZW compression operates on horizontal blocks of the same color. Here are two images that are identical except for a 90 degree rotation. The vertical stripe GIF image is nearly twice as large as the horizontal stripe GIF image. The PNG images are the same size.

Format	Horizontal Stripes	Vertical Stripes
GIF	471 bytes	911 bytes
PNG	232 bytes	221 bytes

Compression and Dithering

A purple shade was created by alternating red and blue pixels.
32× magnification:

200×200px Image, Dithered and Solid

Image Format	Dithered Grid	Solid
PNG	225 bytes	209 bytes
GIF	601 bytes	303 bytes

Transparency

With PNG images, a color in the palette can be designated as "transparent". This lets any background colors or background images show through the transparent portions.

Star Image

Background Image
(satin.png)

Format	Background Color (gray)	Background Image satin.png
GIF No transparency
GIF White is transparent
GIF Blue is transparent
PNG No transparency
PNG White is transparent
PNG Blue is transparent

GIF Animation

• GIF supports animation
• giphy.com

PNG

Property	PNG Portable Network Graphic
Color System	8 bit indexed (256 colors) RGB (24 bit; millions of colors)
Compression	Lossless Compression
Other Features	.png file extension Transparency Animation through non-standard extension
Typical Uses	Any
Property	PNG - 8 bit	PNG - 24 bit
Photograph 250 × 188 px	25.8 kb (indexed, 8-bit)	81.9 kb (RGB, 24-bit)
Illustration 148 × 179 px	1.02 kb (indexed, 8-bit)	1.89 kb (RGB, 24-bit)

Compression for Indexed PNG

PNG images use a different compression algorithm than GIF. Note that for PNG, the vertical and horizontal striped images are the same size.

Format	Horizontal Stripes	Vertical Stripes
PNG	232 bytes	221 bytes
GIF	471 bytes	911 bytes

Compression and Dithering

A purple shade was created by alternating red and blue pixels.
32× magnification:

200×200px Image, Dithered and Solid

Image Format	Dithered Grid	Solid
PNG	225 bytes	209 bytes
GIF	601 bytes	303 bytes

Transparency

With PNG images, a color in the palette can be designated as "transparent". This lets any background colors or background images show through the transparent portions.

Star Image

Background Image
(satin.png)

Format	Background Color (gray)	Background Image satin.png
GIF No transparency
GIF White is transparent
GIF Blue is transparent
PNG No transparency
PNG White is transparent
PNG Blue is transparent

WebP - Web Picture

• WebP
• Compression can be "lossless" and "lossy"
• Supports transparency
• 20% to 33% smaller than corresponding JPEG or PNG formats

358 kb WebP vs 538 kb JPEG

1920 x 1280 px

SVG

Vector aspect make SVGs a powerful format. They are inherently responsive to different sizes using the same image file!

Property	SVG Scalable Vector Graphics
Type	Vector
Color System	RGB
Compression	Lossless Compression
Other Features	.svg file extension Transparency XML format Uses CSS properties!
Typical Uses	Illustrations (logos, icons) Vector Art
Illustration 300x300px	575 bytes compressed; 1.7 kb uncompressed

Basic SVG Shapes

Basic Shapes in SVG 1.1

SVG:

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN"
  "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
<svg width="300" height="200" xmlns="http://www.w3.org/2000/svg" version="1.1">
  <rect x="100" y="100" height="30" width="70" rx="10" ry="10"
    style="fill:green; stroke: black;"/>
  <circle cx="50" cy="20" r="15" style="fill:red; stroke: black;"/>
  <ellipse cx="60" cy="75" rx="15" ry="40" fill="yellow" stroke="black"/>
  <line x1="10" y1="3" x2="30" y2="70" stroke-width="5" stroke="magenta"/>
  <polyline fill="none" points="160,15,170,25,180,15,190,25,200,15,210,25,220,15"
    stroke="blue" stroke-width="3"/>
  <polygon points="100,80,150,40,200,60" fill="orange" stroke="black"/>
  <path d="M0 0 C 10 20, 30 20, 40 0" style="stroke: black; stroke-width: 3px; fill: transparent"  transform="translate(-20,-30)"/>
</svg>    

SVG - Increasing Importance in the Future

• Vector (size and resolution advantages)
• HTML5 canvas element
• CSS control
  • CSS stylesheets
  • SVG style attributes same/similar to CSS properties

Colorado State Flag

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
  <svg xmlns="http://www.w3.org/2000/svg" width="1800" height="1200">
  <!-- Created per specification at http://www.50states.com/flag/coflag.htm by Robert Fleming -->
  <!-- from https://en.wikipedia.org/wiki/File:Flag_of_Colorado.svg -->
   <rect width="1800" height="1200" fill="#002868"/>
   <rect width="1800" height="400" y="400" fill="white"/>
   <!-- 76 + 180*sqrt(55)/36 ~= 113.1 -->
   <path d="M1130.81,750A400,400 0 1,1 1130.81,450L760,600Z" fill="#bf0a30"/>
   <circle cx="760" cy="600" r="200" fill="#FFD700"/>
  </svg>    

Harvard Division of Continuing Education Shield

Icons

SVG Example - Molecule Viewer

Molecule Viewer

Comparison of Image Formats

Graphics Formats for the Web

Property	GIF Graphics Interchange Format	JPEG Joint Photographic Experts Group	PNG Portable Network Graphic		SVG Scalable Vector Graphics	WebP
Color System	8 bit indexed (256 colors)	RGB (24 bit; millions of colors)	8 bit indexed (256 colors) RGB (24 bit; millions of colors)		RGB	RGB
Compression	Lossless Compression (LZW; horizontal repeating units)	"Lossy" Compression (compression optimized for gradual color changes)	Lossless Compression		Lossless Compression	Lossless and Lossy
Other Features	.gif file extension Transparency Animation	.jpg and .jpeg file extensions No Transparency No Animation	.png file extension Transparency		.svg file extension Vector-based Transparency XML format	25% smaller than equivalent PNGs and JPEGs. Supports transparency
Typical Uses	Illustrations (logos, icons) Animated banners and icons Images with small dimension	Photographs	Any		Illustrations Graphs, Charts, Maps - 'plain' and 'interactive'	Any
Property	GIF Graphics Interchange Format	JPEG Joint Photographic Experts Group	PNG Portable Network Graphic		SVG Scalable Vector Graphics	WebP
Photograph 250 × 188 px	29.3 kb	16.8 kb	25.8 kb (indexed, 8-bit)	81.9 kb (RGB, 24-bit)	N/A	9.6 kb
Illustration 148 × 179 px	1.47 kb	6.12 kb	1.02 kb (indexed, 8-bit)	1.89 kb (RGB, 24-bit)	0.575 kb (compressed, 1.7 kb uncompressed; RGB, 24-bit)	0.724 kb

Cartoon Art

GIF	PNG	JPEG	SVG	WebP
GIF 1,511 bytes	PNG; 8 bit 1,031 bytes	JPEG (Quality 100) 14,660 bytes	SVG 575 bytes (compresssed)	WebP 725 bytes
	PNG; 24 bit 1,944 bytes	JPEG (Quality 6) 1,530 bytes

Original image from the works of David P. Heitmeyer

Wordmarks

• hes-wordmark.svg SVG 95 kb
• hes-wordmark.png PNG 109 kb
• hes-wordmark-93.jpg JPG (Q 93) 159 kb
• hes-wordmark-80.jpg JPG (Q 80) 132 kb
• hes-wordmark-60.jpg JPG (Q 60) 93 kb

Maintain aspect ratio for images

If you have an image and are setting the size via CSS, make sure you constrain in only one axis (one direction) - either height or width. Let the other direction scale as appropriate.

Otherwise you will squish or stretch your image.

See the Pen Aspect Ratio and Object Fit - Avoid distorting images! by David Heitmeyer (@dpheitmeyer) on CodePen.

Working with Images

Graphics Tools

• Pixlr (Web, Desktop, Mobile)
• Adobe
  
  • Harvard instructions for Installing Adobe Creative Cloud software, including Acrobat, Photoshop, etc.
  • Adobe Photoshop
  • Adobe Illustrator
• Gimp (Open Source)
• Corel
  • PaintShop
  • CorelDRAW
• Gravit
• Acorn
• Affinity Photo (Mac Only)
• Sketch

Command Line Tool

• ImageMagick
  Creating thumbnails, converting formats.

Services - imgix

• imgix

Imgix

• imgix.com
• Make your images available; get different versions or maniuplations via URL parameters

Manipulations

• Original Image - Glacier National Park
  https://cs12.imgix.net/gnp06.jpg
• Different widths:
  • ?w=240 - 240 px wide (aspect ratio maintained)
  • ?w=480 - 480 px wide
  • ?w=960 - 960 px wide
  • ?w=1920 - 1920 px wide
• Different formats:
  • ?w=1024&fm=jpg - JPG
  • ?w=1024&fm=png - PNG
  • ?w=1024&fm=webp - WebP
• Different compression quality:
  • ?w=1024&q=70
  • ?w=1024&q=30
  • ?w=1024&q=10
• Auto: ?auto=format,compress,enhance&w=1024

imgix and thumbnails and cropping

Large image:

Thumbnail images and cropping

• Thumbnail - 300 px wide:
  ?w=300
  
• Thumbnail - 300x300 cropped:
  ?w=300&h=300&fit=crop
  
• Thumbnail - 300x300 entropy cropped:
  ?w=300&h=300&fit=crop&crop=entropy
  

Finding Images to Use

• Unsplash. “Photos for everyone. Unsplash is internet’s source of freely usable images.”
• Pixabay. “Pixabay is a vibrant community of creatives, sharing copyright free images, videos and music. All contents are released under the Pixabay License, which makes them safe to use without asking for permission or giving credit to the artist - even for commercial purposes.”
• Pexels. Free stock photos and videos you can use everywhere. ✓ High-quality ✓ 100% free ✓ No attribution needed
• unDraw. Open source illustrations for any idea.
• Creative Commons Search. “Browse over 500 million images, available for reuse. All our content is under Creative Commons licenses or in the public domain.”
• WikiMedia Commons. a collection of 85,454,985 freely usable media files to which anyone can contribute

Placeholder Images

placeholder.com is a free image placeholder service for web designers, serving billions and billions of images each year.

You can specify image size & format (.GIF, .JPG, .PNG, .WEBP), background color & text color, as well as the text.

https://via.placeholder.com/300x150/a51c30/ffffff.png?text=CSCI%20E-12

• 300x150 – dimensions
• a51c30 – hexadecimal color of image
• ffffff – hexadecimal color of text
• .png – image format
• ?text=CSCI+E-12 – specifies text

Other examples:

• https://via.placeholder.com/400x200/007A33/ffffff.jpg?text=Boston+Celtics

  

• https://via.placeholder.com/600x225/BD3039/0C2340.webp?text=Red+Sox

  

• https://via.placeholder.com/300x150/FFB81C/000000.gif?text=Boston+Bruins

  

Start with Original PSD/AI/etc. or High Resolution PNG or JPEG

• If you contract out: get the original/source files!
  Keep track of them!
  Make sure others know!
• Always start with the original file format (e.g. PSD, AI, etc.) or high-resolution PNG or JPEG.
• Size images accordingly!
  • Don't shrink full-resolution images by using "height" and "width" CSS
  • Don't enlarge images from smaller ones -- you can only go one way (larger to smaller)

Video

• 2001. RealVideo, RealPlayer, 56 kbps
  
• 2021. AV1, HTML5 Browser, Broadband
  Dune
  

What's Changed since 2001

• Better codecs
• Faster CPUs
• Greater Bandwidth
• Standards

Video vs Images

<img src="images/flower.png" alt="flower"/>

Video is Different

• Large volume of data
• Time-sensitive, real-time delivery
• Native (HTML5) players

Formats & Codecs

• File format (containers)
  • mp4, webm
• Codecs
  • H.264, AV1, VP9

Video and the Browser

• HTML5 <video > tag and native player, often configured via JavaScript libraries

Download vs Stream

• Download
  • HTTP Download
  • Progressive download allows play to begin before file download is complete
• Streaming
  • Files in small chunks, delivered by HTTP
  • HLS (HTTP Live Streaming)

HTTP Live/Dynamic Streaming

• Video split into many smaller files
• Different flavors of bitrate (size + compression) are created
• Manifest provides listing of the files and options, including bit rates
• Adaptive Streaming: Video player can switch to best video quality available for the network bitrate it has available

Example Video

m3u8 manifest file from Mux Video

  #EXTM3U
  #EXT-X-VERSION:5
  #EXT-X-INDEPENDENT-SEGMENTS

  #EXT-X-STREAM-INF:BANDWIDTH=2516370,AVERAGE-BANDWIDTH=2516370,CODECS="mp4a.40.2,avc1.640020",RESOLUTION=1280x720,CLOSED-CAPTIONS=NONE
  https://manifest-gce-us-east1-production.fastly.mux.com/.../rendition.m3u8
  #EXT-X-STREAM-INF:BANDWIDTH=1640580,AVERAGE-BANDWIDTH=1640580,CODECS="mp4a.40.2,avc1.640020",RESOLUTION=960x540,CLOSED-CAPTIONS=NONE
  https://manifest-gce-us-east1-production.fastly.mux.com/.../rendition.m3u8
  #EXT-X-STREAM-INF:BANDWIDTH=994068,AVERAGE-BANDWIDTH=994068,CODECS="mp4a.40.2,avc1.64001f",RESOLUTION=640x360,CLOSED-CAPTIONS=NONE
  https://manifest-gce-us-east1-production.fastly.mux.com/9.../rendition.m3u8
  #EXT-X-STREAM-INF:BANDWIDTH=697078,AVERAGE-BANDWIDTH=697078,CODECS="mp4a.40.2,avc1.64001e",RESOLUTION=480x270,CLOSED-CAPTIONS=NONE
  https://manifest-gce-us-east1-production.fastly.mux.com/.../rendition.m3u8

rendition.m3u8

#EXTM3U
#EXT-X-TARGETDURATION:6
#EXT-X-VERSION:3
#EXT-X-PLAYLIST-TYPE:VOD
#EXTINF:5,
https://chunk-gce-us-east1-production.fastly.mux.com/v1/chunk/0.ts
#EXTINF:5,
https://chunk-gce-us-east1-production.fastly.mux.com/v1/chunk/1.ts
#EXTINF:5,
https://chunk-gce-us-east1-production.fastly.mux.com/v1/chunk/2.ts
#EXTINF:5,
https://chunk-gce-us-east1-production.fastly.mux.com/v1/chunk/3.ts
#EXTINF:5,
https://chunk-gce-us-east1-production.fastly.mux.com/v1/chunk/4.ts
#EXTINF:5,
https://chunk-gce-us-east1-production.fastly.mux.com/v1/chunk/5.ts
....continues......

Video Quality

• Frame size
  480p, 720p, 1080p, 1920p
• Frame rate
  24, 30 fps
• Image quality (adjusting lossy compression to work within a bitrate)

Video Hosting

• Youtube, Vimeo
• Wowza
• Mux Video
• Panopto
• Kaltura
• Limelight
• Brightcove

Embedding Video

• "embed" click, copy :)
• More control with JavaScript video libraries. Some are proprietary to the service, others are open.

Examples

• Example 1 - video element and mp4 file

  
                <video controls width="600" poster="images/bigbuckbunny.png">
        <source src="video/BigBuckBunny.mp4" type="video/mp4">
        Sorry, your browser doesn't support embedded videos.
    </video>

• Example 2 - Video JS library and video from Mux Video platform

  <video
      id="my-video" class="video-js" controls preload="auto"
      data-setup='{"poster": "images/bigbuckbunny.png"}'>
  
      <source src="https://stream.mux.com/K7mw8M3qOl5t35gUaYy9FxmYkGcZHMYq7xkwab01Q9MM.m3u8"
              type="application/x-mpegURL" />
  
      <p class="vjs-no-js">
        To view this video please enable JavaScript, and consider upgrading to a
        web browser that
        <a href="https://videojs.com/html5-video-support/" target="_blank">supports HTML5 video</a>
      </p>
  </video>
  <script src="https://vjs.zencdn.net/7.15.4/video.min.js"></script>

Elements of User Experience

• The Elements of User Experience: User-Centered Design for the Web
• Planes Poster - Detailed
• The Elements of User Experience -- Harvard Library Online Resource

5 Planes in More Detail

• The Elements of User Experience: User-Centered Design for the Web
• Simple Planes Poster

Design and UX Resources

• 
  Williams, Robin. The Non-designer's Design Book : Design and Typographic Principles for the Visual Novice. Fourth ed. 2015.

  Harvard Library: The non-designer's design book by Robin Williams

• 
  Krug, Steve. Don't Make Me Think, Revisited : A Common Sense Approach to Web Usability. Third ed. 2014.

  Harvard Library - Don't Make Me Think

Strategy

Clear and explicit understanding of

• What does the company/organization want from the site? What is "success"?
• What do the users want from the site?

Who are our Users?

• Most sites get a variety of users
• Some audiences will be "primary", others "secondary"
• What are the target audience(s) and what are their information needs?

Most sites will have multiple audiences.

What Audiences can be identified?

University of Colorado

Dell

Audience(s)

• Who are they?
• What are their goals?
  • their information needs
  • tasks/actions they are performing

Know Your Audience

• Be clear on who you are building for. Understand their needs.
• User testing, market research, focus groups.
• Feedback from users. Pay attention to what your users do, not just what they say.
• Keep in mind that as number of target audiences increase, difficulty of web design increases.

Audiences for an Academic Department

• Undergraduate Students
  • Concentrators (Majors)
  • Potential concentrators
  • Non-concentrators
• Graduate Students
• Potential Graduate Students
• Faculty
  • Current
  • Potential
• Researchers
• Public

Scope

Define content or functionality requirements.

What's "in" and what's "out" -- or at least what's "later".

Start broad, then narrow and refine.

Content

Questions to ask about content:

• Does it fit purpose of site?
• Does it suit the audience?
• Would your users find this useful?

Approaching a Project

• What content already exists in web or other media types (brochures, pamphlets, statements, etc.).
  • Adapt (or re-adapt) it for the web
• What content would be good to develop for the site?
  • Create it for the web
• Define incremental goals to avoid "scope creep"
  • Initial Phase
  • Additional Phases

Think About the User

Structure

Structuring Content

Organize, Label, (Navigate)

• Organize and Categorize
• Label
• Navigate

Organize

• Strategy-driven: Top-down
• Content-driven: Bottom-up

Plan for Growth

How to?

• Sticky-notes or index cards
• whiteboard or wall

Structural Models

• Hierarchical
  
• Sequential
  
• Organic
  

Hierarchical

Library of Congress Classification

"Q" - Science
"QC" - Physics

Biological

• Kingdom
  • Phylum
    • Class
      • Order
        • Family
          • Genus
            • Species

Catalog of Life

Too deep or too shallow?

Deep

Shallow

Sequential

Organic

Wikipedia.com

Site Architecture

• Topics
• Audience
• Task-Oriented
• Search
• Internal Organization

Label

• Know your audience
• Test your labels (ask your audience)
  • Card Sort - physical or online, e.g. Optimal Sort
  • Ask questions
    • Where can I get a driver for my HP ENVY 5540?
    • What would expect to find in the category of Synergetic Integrated Scalable Enterprise Solutions?
    • What IT degree programs are available?

Labels - Are there conventions?

Categories and Labels from News Sites

CNN

ABC News

CBS

New York Times

NPR

Fox News

BBC

NBC

Al Jazerra

Skeleton

Page Components

• Header
• Navigation
• Content
• Footer

Wireframes and Sketches - "Low" to "High" Fidelity

Tools to consider:

• paper, pencil
• whiteboard
• Balsamiq, Figma, Sketch, Adobe Xd

Sketches

Wireframes

Wireframes - Drawing and prototype

First Low-fidelity Skeleton for a Project

Navigation Systems

Some navigation systems illustrated

Breadcrumb, Clamshell, Tab / Horizontal List, Dropdown

Surface

Non-Designer's Design Book

The non-designer's design book by Robin Williams

Non-Designer's Design Book

The non-designer's design book by Robin Williams

Colors

• Non-Designer's Design Book: Chapter 7, Design with Color

Creating Color Palettes:

• paletton.com
• Adobe Color CC

Home Page -- Don't Make Me Think (Steven Krug)

• What is this?
• What do they have here?
• What can I do here?
• Why should I be here and not somewhere else?

Don't make me think

Don't make me think, revisited : a common sense approach to Web usability by Steve Krug

Three Princples of Usability

• Don't make me think.
• It doesn't matter how many times I have to click, as long as each click is a mindless, unambiguous choice.
• Get rid of half the words on each page, then get rid of half of what is left.