This is ridiculous to me. I open a new tab in my browser and if I know it's a long page with lots of pictures, like some blog or ebay listing, I might postpone switching to the tab with the single purpose, so it loads all the content in the background and the page is completely ready for me to scroll.
If it's combined with infinite scroll it's even worse. In such case I need to manually scroll the page for as long as I need so it starts loading the damned content. Not many things bring me so close to the point of rage.