[jinx]

Andy I got this to work without GIMP. It's a roundabout solution, but it works:

1. Open Photoshop CC.
2. Open an older file that you know AC3D will accept as a texture.
3. Make any change, add any layers you want.
4. Save the file as a different name. Do not change any of the save-as options.
5. Merge the visible layers. Save the file as a different name, and do not change any of the save-as options.
6. Add a blank layer. Save the file as a different name, and do not change any of the save-as options.
7. Save the file as BMP, and do not change any of the save-as options.

This will result in a BMP texture that will load into AC3D.