Not sure about Crapples and IOS - but I have an app on my phone, and a different one on my PC that compresses photos from several megabytes to a couple of hundred kilobytes. Maybe have a look at this app:
https://apps.apple.com/us/app/compress-photos-pictures/id1449007043
The forum only gives you 100mB of storage - and deleting messages won't delete the photos/attachments.
Click on your user name on the top right of the page, then select "My Attachments". You get a page with your storage quota and a list of the pictures and files you have uploaded. I am 41% into my quota.
You've been around a while, so I would think you have a rather full storage.