It all depends on what format the model is in and what program you'll use to texture it. Some formats, I think most nowadays, will use either md1 or md2 types of skinning. An md1 type skinning, where you use top/bottom, or left/right and take it from one image. Others use an md2 type skinning where you have to specify parts of the image for separate surfaces, [like thrawn said, a UV map.] And then there's crazy engines like the Sith engine that will take a different image for every surface.
I think milkshape can do all kinds of formats and skinning methods, though I've never used it. Give that a try. [Oh, and in order to skin a model, it's pretty hard to go from just images and not the model itself.]
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The Devious Server
[This message has been edited by RingMaster481 (edited August 10, 2004).]