I'm afraid the problem cannot be solved by the small plugin you installed earlier. The issue here is different.
Tiled Galleries use Photon, a module allowing WordPress to resize your images on the fly and cache them on WordPress.com servers. However, Photon will fail to cache your images if it cannot access them in less than 10 seconds. Although your images all seem to be accessible in less than 5 seconds at the moment, I suspect that Photon failed to cache them when you published the post.
I've now purged Photon's cache, and it will attempt to cache the images again.
To avoid further issues in the future, I would recommend that you upload and use smaller images in your posts, since they can be downloaded faster and are a better fit for the web.
Let me know if it helps.