Upload .jpg to Google photos failed

I tried uploading a .jpg (obtained from a scan with my Canon Pixma) to Google photos but this failed.
I tried drag & drop and uploading from my computer, both did not work.
The photo is not even shown as a possible upload when browsing on my computer, because the .jpg type is not among the supported file types. .jpeg is present however, so I renamed my scan to .jpeg and lo!, the photo uploads without a problem.
Seems I'm not the only one having this problem, judging from the upvotes on this closed thread on support.google.com > photos.