Not having a good backing-up habit, and missing the work from yesterday, I went shopping. Now I have a SATA-to-USB adapter, and could hook up the old harddisc to my laptop to get the files. In hindsight, maybe I should have checked if an adapter including a power supply for a more permanent setup might have been worthwhile, because this setup isn't that practical.
Emergency backup - looks scary, but works.
Now I hooked up the big screen and tablet and keyboard to my laptop, and now I'm running a dual screen setup, which IS rather fun. *g*
Anyway, quoting_mungo had reported another problem with file uploads, so I concentrated on that stuff. With her troubleshooting I figured out why some png files produced errors, and fixed that.
Plus, I took most of the thumbnail-building and re-wrote into a more general image-shrinking function, with the one building thumbnails wrapped around it. The code is neater, the bug making it not work for gifs is gone, and I added stuff that'll mean transparency in gifs or pngs will be handled properly, rather than given a black background. Yay for people who leave useful code snippets at php.net!
Then there was a scare caused by me not uploading all files. Not so yay.
I'd like to have more results, but I think I'm coded-out for today.