CMYK TIFFs and JPEGs both work. CMYK JPEG2000 images have not been
tested. Adobe Photoshop and some other software generate inverted CMYK
JPEGs. The image is assumed to be inverted if the "Adobe" (APP14) tag is
present. Images can be forced inverted with `-C "CMYK;I"`, and forced
not inverted with `-C CMYK`.
Pillow 2.4.0 added support for JPEG2000 using OpenJPEG 2.0. Because
Pillow calls the format JPEG2000 instead of JP2, we need to rename it to
enable the optimized code path. Should still be backwards compatible.