The GIMP is a very powerful application which has many uses.
GIMP's main use is for the creation and editing of bitmap images. This ranges from the touching up of digital photographs to the creation of digital art or the authoring of logos. The word "bitmap" means that GIMP is mainly designed to work on images that are made up of "pixels" — tiny rectangles which each have a single set color. These pixels are colored in a way to make up images.
The other main method of storing images is "vectors". A vector image is made up of lines, co-ordinates, and fills. GIMP has some support for vector drawing in the Gfig plug-in, but it is not a complete editing environment and shouldn't be used for the creation of complex vector diagrams.
GIMP also offers some image editing features, which are mainly useful for creating small animations since the editing is done on a frame-by-frame basis. GIMP supports writing the AVI and GIF animation formats and can also read MPEG videos.