When I insert an image in a ProBlog blog post, and choose a high resolution image, say 320x400px, and then set the size in the markup to 160x200px, a cached version of that image at 160x200 is served. I'm not sure if that's being done by concrete5 or by ProBlog, but it keeps retina images from working on retina displays.

My intention, as I've done on other platforms, was to serve the high resolution image to all, but scaled to ½ size (it's a small image, after all). That way non-retina displays do what they can and retina display have enough resolution to work with.

Is there a way to fix this behavior?