Twitter would much rather you used its own picture hosting service than Instagram - that's why images uploaded from inside Twitter show as thumbnail previews while Instagram snaps don't.
Now Twitter has actually sent a message to some of its more influential users to tell them to stop using Instagram so much. "Post your photos directly on Twitter to make sure your fans always see them," reads the prompt.
In other words: we don't want your fans clicking through to another platform. Mashable says the message has been received by celebrities in sports, entertainment and the media.
Turn up the tweet
The issue dates back to 2012 when Instagram pulled support for the Twitter Cards interface, forcing users to click through to Instagram from a tweet if they wanted to be able to see the picture.
If you're a super-celebrity like Justin Bieber, that's a lot of clicks and a lot of traffic you'll be directing just through your choice of photo hosting service. Twitter has tried to hit back through its own set of image filters and editing tools but Instagram remains the app-of-choice for many photo sharers.
We couldn't find evidence of any big names on Twitter who have talked about getting the directive publicly, so it may only be a small-scale test by the micro-blogging network. Nevertheless, it demonstrates the battle these apps face to keep users locked into their own platforms.