As you work on a photo in Camera Raw, you’re undoubtedly going to want to see what it looks like in comparison to the original. Well, Camera Raw doesn’t really have a side-by-side preview, but here’s the next best thing: When you’re in Camera Raw, there’s a Preview checkbox at the top right of the image preview. You can turn it on to see your changes or turn it off to see the before view of your photo. However, that’s kind of lame. Instead, just hit the letter P to toggle the preview on and off.