I have been using my Windows version of Diarium to journal and when I finish every evening I manually go to settings>backup diary.
I am doing it this way until the end-to end encryption feature is rolled out because of the iCloud limitations with security and "Advanced Data Protection" not being able to sync, anyway, every night when I backup I notice that despite my adding "pages and pages" of writing and dozens of photos and other media, my backup size doesn't seem to get any bigger! it seems to be always a particular size. I have attached a screenshot. Tonight I added 25 photos and around 1200 words plus audio. but the size stayed the same - so I tried changing the backup name but that didn't make any difference.