Custom properties don't show up when re-opening the image

[Napia]

After adding multiple custom properties on a new added (and saved) image with empty fields, then closing the image and re-open it, the fields are empty again. Only after saving the resource, the values are present.

Also, it is not possible to add custom properties to a newly added image before saving the image. It throws an error when saving the resource. Deleting the custom properties doesn't solve the problem, you can only save the resource after deleting the image.