As I understand it, once you upload a picture to the GALLERY, there is no way to later change just the picture. You must delete the file along with all the text and any comments that are associated with it.
I am certain others, including perhaps Joe, will confirm that.
Craig
That was my previous "workaround" for lack of knowledgeable alternatives on my
part. Create a new file, copy the details, add a new image to the new record, delete the old record and save the new record.
Stupidly, such a coin appears as "new" although it may have been published months ago. And you lose comments - where there might also be
good information about the coin.