Distorted Featured Image Preview

Hello!

I love highend more every time I use it.

On my site http://www.ShareMySecret.org I am having a problem with the featured images for posts being distorted in the widget. At http://www.sharemysecret.org/read/ you can see that I am trying both the default HB-Themes widget for recent posts and a plugin.

When I go to the posts page in my dashboard, the thumbnails of the featured images look great, but somehow they are distorting for the widgets.

What should I do?

Thank you!
Christina