Black bars on wallpaper / wallpaper zoomed out

I recently tried modifying my Lock Screen by putting a clock widget on it. I didn’t like it so then deleted it. However now my wallpaper is zoomed out so shows black bars on the top and bottom! I’ve attached a screenshot displaying this. If I change to a different wallpaper the problem is solved, however I like my current wallpaper, especially because it goes dark when dark mode is switched on. Unfortunately it seems to be an image which is not able to be selected in the new iOS so I can’t find it to set it again on a different home screen. Since this problem arose I updated my iOS again to iOS 16.4 but it didn’t solve the problem