Thanks for the additional details and link. I did some testing with the main story from that link, since Reader view does not work with headline/index web pages. Even when I manually enlarge the page, the photos are of much better quality in normal view than in Reader view.
I am now convinced the issue is with the Reader view, not the website. I will be reporting it to Apple as a bug. You can report it as well via this link http://www.apple.com/feedback/
[BTW, the difference between first and subsequent pictures is that the first one is part of the page resources while the others are loaded from other site sources.]