Instagram is rolling out a new feature today on its iOS and Android apps that'll clear up DM confusion. Users could already reply to photos, videos, and reshared posts sent to their DMs with their own photo or video, but now, a sticker of whatever they're responding to will automatically show up in their reply.
Here's a good example from Instagram on what that'll look like:
You can obviously blow the sticker up, doodle on it, or add extra stickers. I know on Snapchat, I always forget what I sent someone, especially if they view and respond to it a few hours later. Instagram's solution of superimposing the content over the reply avoids all that possible miscommunication, plus its an original solution, unlike Stories in general. Nice work, Instagram.