PNG

PNG stands for Portable Network Graphics. It is sometimes a better alternative than the common GIF format. GIF was burdened with patent issues in recent years, and the possibility of license/royalty fees has driven many users into the PNG format in all instances where GIF had satisfied their needs for years.

• Color index table can be reduced more than GIF, so potential exists for even smaller file sizes
• Free (as in beer) open standard file format, with no worries of patent restrictions
• Works great for almost all uses that GIF satisfies (however, see below)

It was only recently that I discovered a major problem with PNG files, primarily for web page usage. The PNG file format has a feature to include gamma and color information as metadata. This is often interpreted differently than the surrounding css colors. If you create a css background color, and expect a PNG file to blend in perfectly, you will often be disappointed. The only thing that appears to fix the problem is to remove the gamma and color metadata from the file using a utility such as 'pngcrush.'