I just responded to a message with images within the hour. It was working for me. But there has been reports of an intermittent problem with uploading photos by sellers. It sounds like you've already been narrowing down the issue to insure the problem is not on your side. Are the browsers you are using updated? And/or are there any updates due on the devices? Sometimes clearing out history can help too. But I'm not sure this will be helpful since you'd already tried using multiple devices. I would contact Etsy via chat and let them know all of this has been done to insure the issue is not on your end.
