dc32f0cfe84def651e0e I installed Element on two user profiles with a different account logged in to each instance. I send photos etc to the other profile through a chat between these two accounts. If you want the photos to retain their image size/quality, you have to tick the "send in original size" box when sending, or zip them in profile 1, send them and unzip them in profile 2.
This is probably one the most convenient options that doesn't involve setting up some kind of cloud. Maybe other messenging apps would be even more convenient for this, like Telegram, but Element is end-to-end encrypted.