Instagram seems to be testing the ability to post multiple photos at the same time with its 10.7.0 version, which is available to some photo sharers, an Android user found out and revealed on Twitter.
This tweet by user Philip Chang shows how it looks like:
The feature is just a beta test, so it might be available to all users in the future.
How It Works
With the feature, users can choose up to 10 photos from their gallery to post on Instagram, according to Droid Life. You can also choose different filters for each image, and upload the photos as an album. Followers can then see the uploaded album, slide through images and like photos as they go through them.
However, Chang warns not to try the feature too many times, since “It won't work. and the Instagram app will be broken.”
You can try updating your app to see if you can test out the feature, if not you’ll have to wait like everyone else when Instagram makes the function official.