You cannot delete a Image URL from the Web UI

If you mistakingly enter a URL in the Image URL field it cannot be removed after. Saving results in an error once the field is cleared.

Start by reproducing the issue in the Web UI: enter an Image URL, clear the field, and save. Trace the validation or save path responsible for the error; done means an accidentally entered Image URL can be removed and saving succeeds with the field empty.

Written by the indexing model from the issue text.