Hi,
I’m having the same kind of issue. Using WP Retina 2x, and images within a post double in size when @2x image is loaded. Logo and other images are fine. The post images have height and width defined. I tried both the suggestions in this comment (and cleared cache just to be sure) and neither seem to work. Turning off height: auto on base.css made the vertical height fine, but the width still doubled. You can see an example here (with neither suggestions added) http://goo.gl/de3fyh

Thanks.