Ideal for complex images and photographs.
Image by Steve ???, at this link
Image by Tambako the Jaguar, which can be found at this website
Great for art with few colors and simple transparency like logos and icons. Displays images with 256 colors or fewer. Supports transparency and animation.
Image can be found at this link
Best for images with large portions of flat colors and text. Similar to GIF, but supports more colors, produces better transparency, and loads faster.
Image can be found at this website