Reading this and looking at the tray, I was reminded of the early 20c. sweet wrapper pictures I have. Possibly, they were imitations of these 'butterfly arts' memorabilia as they could easily be copied using metallic sweet wrappers together with the same 'painting on glass' technique.
This one (left) is a favourite of mine from appx. 1930 & typical of the period. I'm hoping to get some more images later as my camera almost had a flat battery!