A Pixel Pimp is some one who is skilled in the art
of making game sprites
or other such graphics
by creating them one pixel
at a time.
A Pixel Pimp is most likely to use a program such as MS Paint, where they have control over each and every pixel.
Pixel Pimps enjoy creating game sprites and custom sprites for themselves, their friends, or to upload onto a site devoted to videogame sprites.
See also Sprite Artist.