[Plugin: Author Avatars List] Override theme css?

OK this is really annoying but my theme somehow puts rectangular borders around my avatars. I noticed it when I tried adding borders to the images by overriding the plugin css in my styles file. Is there a way to block this effect for the avatar list plugin? I’m not that good at coding so I could use some help 🙂

Here’s my website: http://www.cookingblondes.nl/

Thanks in advance!

http://wordpress.org/extend/plugins/author-avatars/