CSS-Only Masonry Layout

Once this is added to enough browsers, I'll be one of the first to implement it! I have a masonry layout for my portfolio using jquery, but there's a bug with it. Often, the images all load scrunched up at the top. I've made adjustments which fix it, but only for a while, and then it starts happening again. Can't wait for this alignment to be possible with a single line in my CSS.