I've now moved all but about 900 images to a mix of imgbox (not very convenient), imgur (also not very convenient), and imgbb (very convenient).
We'll see how it goes... I'll report back if any problems.
It was quite a hassle (I needed to download the Flickr images since I'd done a lot of editing within Flickr), though much compensated for through reading through and looking at the pics in old reports
.