I can speak from experience as someone who lists a lot of items on Ebay -- the picture mistakes are some of the easiest ones to make. I usually use the previous listing as a template form my next one.
I don't know how many times I had the wrong thumbnail/cover photo with the right title, description, and body photos. Usually people alert me when I have an error. One time, a guy insisted I send him the tool in the cover photo, which of course was much more expensive than the tool I was listing. I should have told him no and taken the negative feedback, but I sent him the hammer he wanted.
Most people on EBay are very nice and appreciative, but you always remember the guys like that one.