Mipmap
From Tech Artists Wiki
Mipmaps are pre-calculated, optimized collections of bitmap images that accompany a main texture, intended to increase rendering speed and reduce artifacts. The letters "MIP" in the name are an acronym of the Latin phrase multum in parvo, meaning "much in a small space".
[edit] Generation
A full range of mipmaps for an image will continually halve the resolution of a texture- so a 64x64 texture will have mipmaps of 32x32, 16x16, 8x8, 4x4, 2x2, and 1x1 (a single pixel). The number of mipmaps can be limited to ensure that the lowest resolutions are never generated and used.
Perhaps the best discussion of concerns for mipmap generation for artists is Kevin Bjorke's GDC 2006 presentation, When Textures and Shaders Collide. Much of the material in this article is taken from that paper.
