TJ/xform: Check crop region against dest. image Lossless cropping is performed after other lossless transform operations, so the cropping region must be specified relative to the destination image dimensions and level of chrominance subsampling, not the source image dimensions and level of chrominance subsampling. More specifically, if the lossless transform operation swaps the X and Y axes, or if the image is converted to grayscale, then that changes the cropping region requirements.