[KhaN]

3ds are meshes
bmp, png, dds are texture/images, its those files you need to load into an image editing software.

But if OZ crash during creating polygon entry, its not because your textures are not in power of 2 (OZ dont go read the image to check if its in power of 2 or not, it just do the association and apply the texture if the texture is correct or make your tri white if its wrong).

EDIT : It can also be an UVM problem.