This is a new format for use on the web that is intended to replace both gif and jpeg with its ability to compress, have millions of colors, and support transparencies. It compresses differently from jpeg, and has advanced possibilities, such as alpha channel (opaque or partly transparent colors). The only problem is that Internet Explorer does not support this format. In 8 bit (256 colors) mode it compresses better than gif.
This is a windows bitmapped image. It is used by Microsoft Windows applications and provides good quality but large file size. Not for use on the web.
Windows MetaFile. Useful for clipart, and can be used to make large area, small sized background files.
An older general purpose format that is virtually obsolete now. Also not for use on the web.
Internal format for Paint Shop Pro and is useful if you want to swap files between these two programs.
Kodak PhotoCD format, used with Photo Developing but most photo processors will save your photos as jpegs if you ask.
Portable Document File. Adobe's file system that allows electronic cross platform sharing of documents.