For those of us who are new to the gaming scene, textures are
the "pictures" or images applied to the surface area in a game.
In a 3 dimensional game, before being able to "texture map"
(texture mapping is the act of applying textures) an area you
need to have an original wire frame mesh, or outline of the
area. For instance, think of a house with only the wooden frame.
Next, you need to apply the texture or "picture" to the wire
frame mesh to cover up the frame. Just like covering the house's
frame with dry wall, or a skeleton with skin. Now, there are
different "sizes" or resolutions that this texture can be applied
on top of the wire frame mesh. For example, a texture with a
resolution of 64x64, is 64 pixels wide (pixels are the little
dots which make up an image), by 64 pixels high. A texture with
that low of a resolution would require that more textures be
applied to the area making the area's texture look blurry, or
unrealistic. Hence, a single texture with a higher resolution,
say 512x512 means you can apply the same area with a more "compact,"
sharper and more realistic looking image.
images below show the difference between 256x256 resolution
textures (right) and 512x512 resolution textures (left). Both
screen shots were taken from the win32 Quake 3 test, running
at a resolution of 800x600 using 32bit color. Click for a larger
image. As usual though, you really need to see it in the game
because screen shots almost never do it justice.