I will ask this again: If I could search for the string "picasaweb" in all of my 2000+ posts, I could go through and re-link any images to google photos... The photos are still there, just at the new site. The "search" function doesn't seem to search within links in posts though. Can you find some clever way to do this?
[ed. Again, I’d ask folks to take a moment and think about just how much disk space and bandwidth we are talking about here if I were to host images, regardless of the size.]
If we assume each of your 22,000 members uploaded 1000 images, and each one was limited to 500kb each, you'd need about 11TB of storage. But we both know that a lot of visitors to VAF don't post anything at all. Many only post text. Some post images, and a few post a lot of them. So an "average" of 1000 photos per member is probably vastly over-estimating the storage requirements. I would bet that all of the photos currently linked to (via active links or old broken ones) could be resized to no larger than 1200x800 pixels each and stored on a 1TB drive.
Can you collect any stats that show how many photos are linked off-site from posts, or how many page-views you have on said posts? That might help you better understand the requirements.
When Picasa shut down, it rendered dozens of posts here useless. I kept a list for a while in hopes that you might find a way to search for the photos so we could re-link them to Google Photos, but that didn't happen so I stopped tracking them. As other hosting sites fall (or even just change their internal file storage structures as they expand) the problem will continue.
Anyway, enough for this round. I'll let it go for another year.