There were a few bugs with the image proxy/optimising thingo, so that some images were getting rejected by the Smush.it API and thus not loading at all.
A few other images were having random transparent characters inserted into the URL, so they were returning 404s.
The thread icons feature has been removed hidden, as it provides no usefulness in the slightest. (and it was ugly with the default images)
If you notice anything broken, be sure to let me know.