Single product gallery images not loading instantly

Hello,

First of all I’m not sure if this should be posted in woocommerce support or here, but anyways i will ask and explain my issue.

So I’m working on website optimization and i stumbled upon the single product gallery images not loading instantly while other content is loaded instantly without any buffer.

First i thought its because the product contains a lot of information on webpage but it is not. I am around 90% sure that it is animation / jquery waiting for content load but i can’t seem to find it anywhere.

So lets look here https://bmu-verlag.de/books/java-programmieren/ | This is a product with a lot of information in it, everything loads pretty much instantly except that gallery is waiting for either document load or it is animated.

Now if you look here https://bmu-verlag.de/books/thing-for-testing/ | This product has 0 content, only gallery and review section that is being loaded, but still gallery is not loaded instantly.

Now my question is , what can i do about this? I was digging through single-product.js and i couldn’t find anything useful so if anyone has a tip or some kind of help that would be awesome.

Thanks in advance,
Stefan.