There is no way to get an accurate bumpmap from a photo's colors.

There are Hi lights, mil-tones , and shadows on every thing in a photo.

People have tried for years to make one that is semi accurate, but have all failed miserably.

The closest you can get is using Zbrush or Blenders sculpting tools. You make an image "onion skin" over a subdivided plane, then manually paint where the bumps go.

In blender you can see this in real time if you enable the GLSL shaders, Zbrush it is always in real time.

The PNG heightmap resolution in Voxed is limited to 256x256 and the map is 512x512 so you're better off using the bitmap converter if you want a full map.

http://ace-spades.com/forums/topic.php?id=1023

I know how to paint PNG images onto the map, and how to wrap them onto objects, but I can't make it so that all the darker areas are crevices and the lighter areas are peaks of mountains as some maps have done already. I read in the instructions something about using the "ins" button in conjunction with V to to turn a picture into a bump map so that your map automatically writes a texture in relation to the actual image. Can anyone help? Sorry if the question is kind of vague.