ie is stretching cached images loaded asynchronously

Question

I am loading images via ajax on my website. They load in a container with a max-height of 600px. The images are set to have a height of 100%. They load in perfectly the first time but come out streteched very wide when stretched.

.gallery {
height: 600px;
overflow: hidden;
padding-left: 35px;
}

.gallery img {
height: 100%;
}

here is an example of the problem

http://alexpenny.com/post/1065000657/we-shot-in-the-nau-studio-and-i-took-some-shots