I dreamt that someone said they were very interested in joining this thread. Nice photo! And this is interesting. I wanted to see what kind of webpage it's from and found it with a reverse image search, but clicking it just leads me to scam pages... I wonder if that was always the case! Here's another photo.
I'm not sure if this is a joke about the discussion of HO vs H0, a joke about the exclamation 'Oh', or both.
This picture is hosted on the internet archive! . EDIT: Oh, and they also host the song itself and a larger version of the image! They also provide a bit of context. https://archive.org/details/victor-17874-a-its-tulip-time-in-holland
Cool! I didn't listen because I'm currently listening to other music, but thanks for sharing the archive.org page. I also found that one and a half million copies of the sheet music were sold!