Not sure if I am seeing what you are seeing,
You may want to post the project so we can see how you are linking the images but from what I can see and you screenshot confirms. You are loading 183 + MB of thumbnails.
So even when you click on one of the selection areas on the Publishing page soon as the page comes up to see the thumbs The thumbs are still loading..
I would not preload all the thumbs but try and load them as needed. This is called Lazy loading
Note, below is the first link I came across re lazy loading. It is more of what it is than how to do it within Hype.
In this link is what @Daniel posted regard lazy loading plugin..
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Update,
Think I found why you are loading the server images.
You have entries like this in your functions.
"url(images/Cards/" +str + ".jpg)";
it should be
"url(${resourcesFolderName}/" +str + ".jpg)";