You may check this thread http://forums.appthemes.com/featured-image-thumbnail-size-6772/page-11/ .
You may check this thread http://forums.appthemes.com/featured-image-thumbnail-size-6772/page-11/ .
I noticed that there are category names (eg. Arts Jobs - Entertainment Jobs - Publishing Jobs) very long that also interfere with alignment.
I believe it is a conflict and so access your server files using an FTP application and delete the plugin.
use a decent php editing software with syntax highlighting and error reporting, i recommend Nusphere phpIDE, you can download a trial from their website.