If I go to settings -> iCloud -> manage storage There are 2 categories:

1. Backups (118 GB)
2. Photos (18.3 GB)

In my backups, there's photo library (109.25 GB) I'm confused, what's the difference between storing my photos in iCloud and backing them up then storing them in iCloud. What happens if I click on " turn off and delete" the backup for my photo library?