Story time! I started noticing that my iTunes backups of my phone were taking forever, and were getting very large. I couldn't figure out where the space was going, so I used iExplorer to find out what the tens of thousands of tiny files were in the backup. It turns out it's my iCloud Photo Library. Not just images that happen to be downloaded full size, but the intermediate data too! Thumbnails of different sizes (I could find two smaller sizes per image) add up to a LOT of tiny files, slowing the backup down big time. There is absolutely no reason to back this data up, because it's already in my Photos.app library, which in turn is backed up with Time Machine AND obviously in iCloud itself! I know I can just use iCloud backups, but I like to occasionally back up to iTunes too for redundancy. iCloud is nice but I don't trust it as my only backup. Is there any way to keep iTunes from backing up this data?