Thumbnailing a file (either uploaded or linked) used to work, now it does not. Simply put - when I try to either upload a new thumb, or link to a thumb, and hit "Update" (or Save on the back-end), the browser window acts like it is processing, and then proceeds to show me a completely white/blank screen.

I attempted to work with this on the front end a little bit, and now I am no longer presented with the option to modify the thumbnail on any file inside the Album. Files that have existing thumbnails aren't able to have those thumbnails modified - the option when editing the item no longer exists in the UI.

When attempting to remove them so I could re-add them, the response from the front end I received was: "414 - Request-URI Too Large - The request URL is over the maximum size allowed!"

I am wondering if this had something to do with the thumbnail update failing. Note: I am using Chrome v80.0.3987.149 (Official Build) (64-bit)

As of the time of error reporting, all core and plugin files were up to date. We just released the website today, and were in development mode over the last month - I check the CB code quite often for updates.

The thumbnail I was attempting to place on a file was only ~28KB in size, well under thumbnail limits. And I verified it wasn't corrupted in any way by opening/re-saving in multiple image editors.

I was attempting to manage the file inside the album both from the front-end and the back-end using a SU account. Both experienced the same issues with a blank screen and no thumbnail update.

As a sidenote: this may be related to the problem I just reported about the blue Download button on files not working when they are 'linked' files - it only works for us when the files are uploaded using CB Gallery. I haven't re-tested since I switched from linking the files to uploading them. I will make a new hidden test album this weekend and see if thumbnailing on uploaded files works.