I'm seeing a turquoise blank canvas when the puzzle is first shown. If I browse the Gallery and pick an image, then it works.
I'm also seeing 404 errors in my log for attempts to access the names of the images in the wrong directory. The files are trying to be read from the current upload directory (which contains the current month and year), but they actually are in a gallery directory.
That image is actually in the directory
Maybe that is an attempt to read a cached image, but there are dozens of failures so caching (if any) is not working. I see no error messages being given in the puzzle area.
I'm also seeing many attempts to access the default images, probably due to the other failure.
More oddly, a URL without the double-slash after http, and looking in my local puzzle gallery for a default image instead of the images which actually are in that directory:
(actual URL edited to example.com)