First of all: this is a very nice theme, thank you!
I've found that blog posts which are displayed when I use the archives widget (so the URL becomes something like "http://site.net/blog/?m=200807") have no clickable links anymore and no pictures.
It doesn't make a difference whether I use the "dropdown" variant of the archives widget or not.
Since I can't reproduce this problem with a different theme, my guess is that something might be wrong with the plaintxtblog theme. Obviously I may be totally wrong.
Thanks for your attention!