This might not actually get you more clicks
... but I've noticed some of your thumbs are like 20kb... you could make them half that size and still keep the quality. It would improve your site's loading time. To do so you could open them in PS and File > Save for Web and Devices ... pick jpg and change the quality to about 75-80... The change it the look would not be that noticeable but the loading speed will.
Good Luck