When someone follows a MediaViewer hash URL and there is no such image on the page, the behavior is not very graceful (black flash, then just show the page). We should show a message explaining the user what happened.

There are multiple possibilities:

• the image was removed from this page but is still on the wiki - we can just link to it
• the image was deleted / moved / oversighted / etc we can send the user to the logs
• there is no trace of such image ever existing - tell the user that the link is wrong