I’m using
$content_width = 560;
to make the maximum image width in wordpress to 560px. However, whenever I upload an image in my custom post type, the “Large” option size is disabled and the only small, medium and actual size remain… Any idea why this isn’t working?
Look under Settings > Media and see what you have as the large setting. I’m guessing that it’s 1024×1024 (the default)
When your image has been scaled to 560 wide, the actual is now smaller than the large (typcially not the case). WordPress is smart enough to figure that out, and let you know by removing the large option.