Rounded corners of images?

I am still new to this theme and I am wondering if there is a way to round the corners of the pictures I insert in my posts with this theme? I have been having to round the corners in photoshop one by one and then post them on my blog but I'd love to have a quicker way to have them automatically be rounded if its possible, any help would be appreciated, thanks! www.joannalynnphoto.com