Safari (MacOS 12.3 beta seems to have a finite time period to download images otherwise it doesn't load some webpages. Right now I am not seeing it happening. Usually during day it has more issues with this URL.
But if I still go to the largest image size reload and then spin track ball down I can see Safari unable to fully draw the bottommost jpegs as fast as the top ones. Comparably you look at the same URL with Firefox 97.01, reload page, and scroll down fast all those same images show almost no latency with the redraw. It's that much quicker.
Safari should be more optimized, it's slower than Firefox in loading all content on pages with lots of graphics , and that contributes to some webpages failing to appear completely, partially and sometimes barely anything.
Also note I am doing this on a 24" iMac with default resolution.