Hm. I think the images should be included in the downloaded bundle…? When I download that notebook and run it locally, I see them under /files, and the notebook works locally.
But, the way file attachments are implemented, folks have often had issues bundling them in other applications. Here’s Radames talking about it in the forum; we have an example using Rollup here.
Maybe you know all that; I’m not sure what itch.io is doing here. I’m too sleepy right now to understand the error there on that site ha but can look more later.