Site crashes on safari and iPhones

after I launched my site, I got a lot of people reporting the site crashing on their iPhones and Safari Browsers. Always when they start scrolling the site crashes. Apparently safaris cache is filling up rapidly. I kept all the pictures really small and all other browsers work perfectly.

Does anyone have an idea, what I could change to get it working.
Thank you!

the site:
example of a crash: Imgur: The magic of the Internet