To get photos to work most easily, open Choose File, then select Take Photo or Video and snap a picture of the item, then hit Add File. That usually works! Apple’s new file format .hei does not work for uploaded pics. There is also an issue sometimes with .jpg vs .jpeg as the extension. Taking the photo using the steps above skirts those issues, but you still may have to limit the resolution on your phone if the file size is too large…

Another cheat code is to take a screenshot of your base picture

On android platform it is saved as a png extension and the site accepts this lower resolution format