A little while back the bumpmap textures got fixed, couple versions ago I think. It's not gotten much attention though, due to the slight effort in using them.
The use for a bumpmap texture is to affect the per-pixel lighting that a normal texture receives, which increases a texture's dimension a good bit by highlighting or shading different areas. If the art has smooth shading already this will have the best result.
How you get a bumpmap texture to work properly takes a little bit of doing. The original texture you have is not in the proper form for the computer to "see" the dimensions.
This is where a thing called 'normal mapping' comes in. You'll need to put your art through some software (there's all sorts of tools online) that will change it to a perceivable medium.
Upload the modified texture alongside your original, and you should be set.