Beginning today, you'll be able reply to a photo or video in your DMs with a photo or video of your own, which will include a sticker of what you're replying to. So, if it's a photo of a cute puppy you're fawning over, your reply will have a sticker of that cute puppy. If it's an ice cream cone, you'll get a sticker of that cone. And so on, and so forth — you get the picture.
As The Verge points out, the inclusion of the sticker ensures there's no confusion over what your photo is being sent in reply to. Simply tap "reply" to turn on the camera. The sticker will appear as a small rectangular icon in the upper right hand corner, which you can then move around, resize, and draw on as you see fit. You can't get rid of it, but if you really don't want it on screen you can move it to the edge so that it (almost) completely disappears.
The true genius of today's update, however, is a new split screen reply mode. Follow the same process above, tapping "reply" to turn on your camera. This time, instead of moving around the sticker that appears, tap it once to activate the split-screen.
There's room for all sorts of ridiculousness — and some creativity, too — with this option. It all depends on how you position yourself in the photo, as the example below shows. You can also draw and add stickers, per usual.
If you're not a fan of the split-screen, just tap the sticker to revert it to its original size. The only downside is that you don't seem to be able to control what appears on the top and bottom of the split screen — whatever you are replying to will always be in the upper portion. In the example above, that means that while you can't have a puppy's body, you can most certainly have its head.
This split-screen format mirrors the one the app is testing with its new two person live stream; we're officially at the "let's go halfsies" part of the Instagram era.