if BW isn't a problem and now days it is less and less, then you could make it easier to upload / store photos in posts
that way they are always on your server
Linky Pooto something i've done for about 10 ubb.threads customers now
works great
there is also an option to have the image uploader upload from URL and autosave on your board when peeps post..
an additional feature (not yet mentioned) is that the posts are tied to the USER_ID, which immediately gives users their own 'personal' gallery of sorts