GIF, JPG, & PNG- Who, What, Why, & How

http://www.sitepoint.com/article/gif-jpg-png-whats-difference
-By Matt Mickiewicz and Nicky Danino

These are different file types for storing graphic information. The most popularly-used is probably the jpg which can support 16.7 million colors & is intended for storing photographs. However, because of the need to compress to store information, a jpeg loses information from the original image with each save. That information cannot be regained. Jpgs should be used to save photo graphs or images that do not look better with only 256 colors.

A gif file supports a maximum of 256 colors & is ideal for images with large areas of the same color. According to the article it is the only way to put animation online aside from programs like Flash. Besides photographs, it is the probably the best way to present most graphics. Gif files do not lose data with compression like jpgs do. Gif's also support transparency which will allow a graphic designer to set the background color of the image & interlacing which allows information stored as a gif to be downloaded on the internet in several stages giving the illusion of speed. Gifs should be used for graphics like logos, line drawings, & icons, but not for photos or images with long stretches of continous tone.

PNG is the newest file form & was designed to improve upon gif files. It supports streaming & progressive file formats. It provides greater range of color than the gif, up to 24bit in color. However, png files cannot support animation, so they will never be able to completely take over from gif files.

~Kate