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: