I'm working on a website which will use images in several different applications, from action buttons to avatars to larger detail images. What factors should I take into consideration to decide whether these images should be jpgs, gifs, or pngs?
- JPG for photos or high color differences
- PNG for images with gradual transparency (fade from 1 color to clear)
- GIF for images with small color palettes
Obviously give each image a try and see what comes out to the smallest file size. The smaller the size the better. Also don't worry about transparency in IE6 for your PNG's, grandma isn't as concerned how your site looks just that she can see pictures of you on it.