iCloud full? Can't figure out what's eating space? Have a look here.
This post isn't a question, it's a piece of knowledge I'd like to share with others who have the same problem as I had.
If your iCloud is closing in on it's limit and you can't figure out what's eating disk space, this is a tip for you: iMessage/SMS/MMS attachments could be the culprit.
I've asked twice in this forum what could it be that's eating space, but no one has pointed me to the source of the problem. Today I found it, iMessage attachments. I've deleted images and videos for the past hour, which was basically duplicates of files I already saved to external drives. No need for those attachments to be clogging up my iCloud at the expense of new photos I take.
Here's how to do it:
http://www.idownloadblog.com/2016/01/26/how-to-bulk-delete-attachments-from-the- ios-messages-app/
iCloud doesn't really give you any hints as to what it is taking up space when it's iMessage attachments, so if you're like me and not interested in buying more iCloud space - check it out.
iPhone 6 Plus, iOS 10.3.3