HOW do I convert an image into one that can be used as a NORMAL MAP!
If you convert a bump map to a normal map you won’t see any real improvement. It would be like converting a greyscale image to RGB. It might render a little faster, but you need a way to create a normal map to get the benefit.
Best way to make a normal map is by baking the texture on a high-polygon model, so the map will wrap seamlessly. That’s probably some kind of sculpting/texturing program like 3D-Coat.
The next best way is to create a tiling (or non-tiling) “flat” texture, either generating it in a paint program or rendering out a flat image of a 3D model (the BAKER plugin can this).
Least-best way is to convert a bump map in a program like nDo - which I couldn’t find a current link to…