{bitmap} concerns handling and processing of images, rectangular indexed domains of data
A bitmap is an image or an indexed domain of data that in the simplest case can be a binary image of ones and zeros or white and black. All graphical image formats (e.g. TIFF, JPEG, PNG, GIF and BMP) are also stored as bitmaps. The bitmap tag is thus not limited to common graphics or photographic files but is a more generic tag.
For more information on the definition of Bitmap see the Wikipedia Bitmap entry.
