Setting the size of a mp_image must be done with mp_image_set_size()
now. Do this to guarantee that the redundant fields (like chroma_width)
are updated consistently. Replacing the redundant fields by function
calls would probably be better, but there are too many uses of them,
and is a bit less convenient.
Most code actually called mp_image_setfmt(), which did this as well.
This commit just makes things a bit more explicit.
Warning: the video filter chain still sets up mp_images manually,
and vf_get_image() is not updated.
d77d9fb933