You'll now notice an "Edit Photo" link under your photos. That link allows you to crop the photograph as well as replace the photo, without losing the comments and likes on the photo. This is useful if there's something about the photo you're not quite happy with, but don't want to lose the comments and likes by deleting and re-uploading.
Cropping is the first function I thought may be useful for this new photo editing system. I can build in more features as the needs arise. Just let me know. I also wrote a piece of code that tries to standardize the color space when a photo is uploaded. I'm hoping this will normalize differences in how brightness and contrast is rendered between various websites.