So I gave it a test for both the landscape and portrait pictures and they loaded okay on a new world save. Perhaps it's the type of file that you're uploading? is it a JPG or PNG?

@Arimmy Thank you for your question, I haven't updated this workshop item in quite a while so it may be the item itself, however it may also be the link. Have you tried multiple links? I'll test it out and get back to you :)

How do I insert and keep my image in the frame? It keeps going back to blank.