changed: - GEM supports gray8, YUV, and RGBA images. If it sees that the number of bits per channel and the number of channels is something that it should be able to handle, it tries to load the raw data. If you have compressed or stored the pixel data in some "strange" format, then GEM will probably not read the information correctly. Also, if it is an RGBA image, then make sure that the alpha channel is something useful (this only matters if you are using the alpha channel, like in the alpha object or pix_mask).