Flickr has corrected the problem, everything seems to be working again!

Steven wrote:

If you have changed no Juicebox files and your web server has made no changes, then the problem must logically be with Flickr itself.
I have done a quick search on the Flickr forum and it does, indeed, look like the problem is with Flickr. They are aware of the issue and are working on fixing it.
Please see this Flickr forum thread for further details.

Thank you!

I am having the same problem. All galleries give me an error saying "Flickr images not found". I've gone into Flickr and re-tagged some pictures to see if that would fix it. I also updated the Jbcore folder to the updated one. Both have done nothing. I'm trying a full gallery update now, I'll let you know the results...