Model Creator seems to be using a cached version of whatever texture file is imported, meaning any changes you make are not reflected in the program.
To reproduce:
Import a texture file. We'll call it texture.png.
Edit texture.png using your image editing software. Change something and save it.
Go back to Model Creator. There is no change to the texture.
Exit and restart Model Creator. There is still no change to the texture.
This problem is all the worse because you can't manually fix the issue by re-importing since it is often impossible to import the new texture without starting over completely (due to other bugs reported in this tracker). Even if we could re-import the texture, we'd then end up with multiple listings of the same texture in the Images list, which is pretty silly and can't be worked around since you can't remove imported textures from the Images list.
Model Creator seems to be using a cached version of whatever texture file is imported, meaning any changes you make are not reflected in the program.
To reproduce:
This problem is all the worse because you can't manually fix the issue by re-importing since it is often impossible to import the new texture without starting over completely (due to other bugs reported in this tracker). Even if we could re-import the texture, we'd then end up with multiple listings of the same texture in the Images list, which is pretty silly and can't be worked around since you can't remove imported textures from the Images list.