If it's the same issue as in https://discussions.apple.com/thread/251814420, then my solution - https://discussions.apple.com/thread/251814420?answerId=254446243022#254446243022 saved me a day :)

Same thing here. Initially my images were ok, but then became red and IMAGETOOLFAILURE'd xttps://ibb.co/PwtnBbY (replace x to view the screenshot)