Um, no. Bump mapping isn't simply a detail slapped ontop of a texture. You could easily embed such detail directly onto the texture if that were the case.
Bump mapping is about shading. What it does is it causes the appearance of raised bumps, or indented bumps, on a texture. The light ends up shading it differently.
Essentially, bump mapping is the predecessor to normal mapping and parallax mapping.
To get an idea of the visual effect it causes, imagine just a flat square. Now, imagine that flat square with bumps sticking out or into it everywhere. Then imagine a light that moves around. The bump mapping details will be brighter on the side that the faces the light and darker on the opposite side.
So you move the light around and the entire thing reshades constantly, giving the appearance of an uneven surface, even though the surface is infact flat.
(EDIT)
Here is a video that is a good example of bumpmapping
http://video.google.com/videoplay?docid=1570416667092534064
Nothing I say is intended to be rude. My autism means that I do not know what is rude and what isn't rude. I apologize if I seem rude. It is not my intention.
