Instagram is reportedly testing a feature that lets users reshare other users' photos — something users have wanted for a long time.

It would work similarly to Twitter's retweet button, or shares on Facebook.

The experimental feature could transform the photo-sharing app.

There has always been one feature conspicuously absent from Instagram compared to other social networks: Re-sharing.

Twitter lets users retweet other people's tweets onto their profile, while Facebook users can share posts from other users and pages, but Instagram has never added similar functionality.

But that might be about to change: The Verge is reporting that the Facebook-owned photo-sharing social network has been testing a feature that would do exactly that. The tech publication says it has seen screenshots of two reshared posts.

It's not clear how Instagram is experimenting with the feature, or when it will actually launch more broadly — if at all. Tech companies sometimes test out features and tweaks that they don't ultimately implement.

An Instagram spokesperson declined to comment to Business Insider, then later said that "this is not something we are building or testing," and that Instagram has not explored the idea in the past either.

But if ultimately incorporated, the change could have a radical impact on Instagram's feed — opening the door to strangers' material appearing is users feed unexpectedly, and boosting the reach of popular and viral accounts. As The Verge notes, it could also aid the spread of fake news, a persistent problem for Facebook.

However, this is something that Instagram users have wanted for a long time, often turning to unauthorized third-party apps to make it work. In that light, it could well be a popular move.