The 'Texture' is the full color JPG (or TIFF, BMP, etc) where the 'Bump Map' will be your grey scale to add depth to the render. Using Poser4 you will let Poser convert it to a BUM in the Material Window but in Poser5 you just use the grey scale. Many people make the mistake of just converting a texture to grey scale and using it as is, often this is not really what you want to do. Such as with scars, scabs, and wounds you would want CUTS and GASHES to be darker then the flesh, thus they get recesed (lower or 'cut in') where as such things as scars and scabs should be raised therefore you want then slightly lighter (whiter) then the flesh so. You see in a Bump Map the darker areas are lower and the lighter areas are higher. Take a black and white image, about 400x400 will do, and paint white stripes on black...or black stripes on while, whatever tickles your fancey. Now apply this to a non-textured Poser Ball, or use the Box I don't care just do it! Now make sure you apply it to the BUM window if using Poser4 or the Bump node if using Poser 5. Now render it and see the difference. This will give you a good idea of what you are doing to your texture when you apply a Bump Map.