[{{ paag_bitmap_and_bitdepth.png|a) 1bpp\\ b) 2bpp\\ c) 2bpp wide pixels\\ d) shared palette}}] A **bitmap** is literally a map containing bits, just zeroes and ones. How the bits are interpreted ("mapped to" a visual image) depends entirely on the [[graphic_mode|graphic mode]] used to display the bits.

The **bitdepth** of a mode refers to how many bits are used to define the information for a single pixel in the bitmap.

The short notation to describe the bitdepth of a digital image/bitmap is bpp (bits per pixel).

In an indexed image, the bitdepth directly defines the maximum number of different colors any pixel can be: It is "two to the power of bpp", provided the palette contains that many distinct colors.

All three modes in the example here use an identical bitmap.

further reading:
  * [[wp>Bitmap]]
  * [[wp>Raster_graphics|Raster Graphics]]