Instagram's direct messaging features have gotten surprisingly robust over the years. You can send photos privately to another user (or group of users) and share other images you see from Instagram users with just a few taps. (The latter feature is particularly good for sharing dog pictures, just saying.) Instagram also added "disappearing" photos and videos to the mix this past November, one of the most obvious instances of Facebook and Instagram "borrowing" from Snapchat. Today, Instagram says they're combining disappearing and permanent messages all into one thread -- an obvious UI update that seems like it should have been there from the beginning.
Previously, disappearing messages were siloed off in a separate part of the Instagram Direct interface. Those photos and videos showing up at the top of the feed as a bubble you could tap, basically the same as Instagram's stories. Now, all these messages will just be grouped under a single thread alongside all other text, images and photos you exchange with a person or group. Instagram noted that text, images and photo post sharing will otherwise stay the same.
The intention seems to be to letting users more easily continue having a back-and-forth conversation that includes all types of media that Instagram supports. If you're ready to give this a shot, Instagram says the updated app is available for iOS and Android now.