A
raster-based fixed-resolution
pixel layout format. Bitmap images are displayed as
rows and
columns of pixels, all in a neat, perfect
grid. They do not scale well, becuase you will either lose
information if you scale them down or add
guessed information if you scale them up. Bitmaps are the
images which most people are more familiar with.
Besides the image format named "bitmap" (used in Microsoft Paint) (BMP), there are many bitmap-based image formats. JPEG, GIF, PNG, ILBM (LBM), MAC, PCX, PGM, PPM, and TIF are a few examples.
Bitmaps are different from vector-based images, which store shapes, lines and points in an arbitrary-resolution format.