When Instagram Direct launched, users could send a photo to a maximum of 15 people. Instagram announced Direct in December 2013 as a way to share photos and videos privately, contrasting with the service’s earlier emphasis on public posts and follower feeds.
The 15-person limit applied to the original photo-sharing feature: a sender selected a group of recipients, and the image appeared in a private conversation for that group. It was not the same as posting publicly, where followers could see the content according to the account’s privacy settings. Direct also allowed recipients to respond with their own photos or videos.
Instagram Direct later expanded substantially. A major update in September 2015 added conversation threading and made it possible to share locations, hashtag pages, and profiles inside messages. Because messaging limits and group-chat capacities changed over time, modern Instagram users may remember different numbers. This question concerns the original 2013 Direct feature, whose widely reported maximum was 15 recipients.