This is weird. I've been using the theme for years now and I'm pretty familiar with how things work.
I just published an article but when I check it on the front page, it uses a wrong default image from an article that I published a few months ago. If I view the single article, the default image is correct (likewise the thumbnail produced by timthumb). I tried refreshing the cache, turning off the Super Cache plugin, and I'm still getting the wrong default image on the front page. What's also funny is that if I click on that wrong default image, it'll link to the old article that it belongs to.
Any hints to where to look?
This is the front page:
If you click on the main article (title), it'll show you the correct default image.