Just recreated the bug, and sure enough it do happen.
So the way I've been able to upload images is by selecting "Add Image," under "Upload image" I'd select "Pick Image" and finally "Show all files." Beforehand I'd open the screenshot to confirm I have it, edit/trim fat because I have multiple screens, and make sure I know how to pull it up. Not trying to baby anyone here, but if someone else want to know how then they can read this and hopefully be able to recreate.