When I am using a screenshot tool and paste image present in clipboard into a note, Joplin automatically imports it and saves it into a file automatically named with a GUID.
My suggestion is about the automatic naming process. Instead of creating a GUID as filename, would it be possible to naming file with a timestamp instead like ‘yyyyMMddHHmmssfff’ ? To avoid collision, we could add a small random number at the end of the filename just to make sure.
I make this suggestion because I noticed that when you take notes with a lot of screenshots, sometimes, you want to replace some of them because they are not good enough. The problem is that you have to go to the menu ‘Note attachments’ to find the image file you want to delete (to save space) and there is no easy way to find the file.
Naming files this way would help organizing and finding them easily from this menu and also on the hard drive.