iframe links opening in new window- cannot figure out why!!!

[risa]

Can anyone help me figure out why my links (under the portfolio section) are opening in a new window and not in the iframe? I am having this problem in every browser except firefox. It used to work fine, and suddenly stopped. I've been trying for a while and I cannot get it to work properly. Please help!
The website is www.risanicole.com
Thank you!!