I've modified a plugin called Google Analytics Popular Posts ( http://wordpress.org/extend/plugins/google-analytics-popular-posts/ ) to show featured image thumbnails in the popular posts. For some reason though it takes the site down a couple hours after I post it but works fine when I first post it.
Here's the code that fails:
Here's the code that works:
Here's the before/after of the output (after is on the left):