imageproxy breaks some feeds when using the web client. I noticed in another bug report that you disabled it for Android; you may need to do it for the web interface too. Or at least have an option to disable such URL hijacking.
Here’s the html for one such broken image:
<img alt="external_image" src="https://imageproxy.newsblur.com/sc,sA1UzpWsX1YXKGiHozi63bR51C7x8_JNHmggnRyasoMI=/http://www.kdca.go.kr/html/a3/namoimage/images/000033/Press_Release_(November17)001.png" style="border: 0px solid rgb(0, 0, 0); border-image: none; vertical-align: baseline;" title="external_image">
Trying to open that png directly works fine.