Image Zoom

I'm using the Beep Edition 7.x-1.1 theme with Drupal Commerce 7.x-1.9 and the Image Zoom 7.x-1.2 module. I added the following to the Image Zoom CSS to get the product image to display less than 100% of the page:

.imagezoom {
	img {
	  width: auto; 
	  height: auto;
	}
}

I then replaced max-width: none with max-width: 100%; on a zoom image id to get the inner zoom to work.

But a strange behavior is now happening. Each time I mouse over the image, the image shrinks a little. Continuously mousing in and out of the image causes the image to shrink to virtually nothing. I've tried adding max-width: auto; to different image classes with no luck.

Setting the .imagezoom class to a fixed pixel width produces the same result. You can try mousing over the image here.

Any help is appreciated.

BTW, this behavior is not exhibited with a different responsive theme.