The list of raster formats supported in the default distribution for reading and writing includes the following:
Note that with the exception of PostScript, the GIMP only supports raster images. An alternative to this format is known as vector format images. These images are commonly used on Microsoft systems and carry the .wmf suffix. If you have or need to use these (you can find icons in this format on many CDs available from software stores), you should consider using Applixware's Applix Graphics tool. This program can import the .wmf files and export them in a number of raster formats which can be used by the GIMP. (Applixware is a commercial package.)