This sounds like the "Little Pierre" "we've looked everywhere" "orange raincoat boy" failure that began appearing a couple months ago. Sometimes it clears up if you turn off VPN (if you are using one). Other "fixes" are to add no more than 5 (or so) new pictures each time you do a save. As a last resort, write and save the text portion of the listing on a desktop/laptop and then add the pictures using a cell. Adding/saving a large video file is apparently not a problem.
