Question: JPG are saved as textedit
Maybe this question is not an apple question, I don't know. I will try. I am using FireFox browser as well as Safari on certain occasions. After updating to FireFox 57, all images I drag to the desktop that are jpg are saved as TextEdit. PNGs are OK. My other iMac is OK, so it's not only the browser I suppose.
iMac, macOS Sierra (10.12.5), 27"