Facebook (Nasdaq: FB) photo-sharing service Instagram is making it harder for users to display pictures on microblogging site Twitter Inc. amid increased rivalry between the social-networking websites.

Twitter users are experiencing “issues with viewing Instagram photos,” the San Francisco-based company said in a blog post. Instagram, a mobile-photo sharing service that Facebook bought in August for $715 million in cash and stock, has disabled a feature called Twitter cards for showcasing photos and other media. Photos from Instagram now appear cropped, Twitter said.

Facebook, owner of the world’s largest social network, is stepping up efforts to more directly challenge Twitter, a service that has become the main outlet for many celebrities and politicians to share their thoughts with millions around the world. Instagram, which has more than 100 million users, wants users to go back to its own Web service for viewing photos, Kevin Systrom, co-founder of Instagram, said in a statement provided by Menlo Park, California-based Facebook.

“A handful of months ago, we supported Twitter cards because we had a minimal Web presence,” Systrom said. “We’ve since launched several improvements to our website that allow users to directly engage with Instagram content through likes, comments, hashtags, and now we believe the best experience is for us to link back to where the content lives.”

Driving Traffic

The policy change better prepares Instagram for generating revenue from its service by driving traffic to its own properties where it might show advertisements, said Michael Gartenberg, an analyst at Gartner Inc. Facebook and Twitter are fighting for the attention of users, who have only so much time to devote to one service or another, he said.

“There is no doubt that the two services are going to begin to clash,” he said. “This is an interesting move and it will again affect users, who I think in many cases count on Twitter to share their Instagram pictures.”

With Twitter’s card feature, outside developers are able to display the content that is linked to their services. That can include text, photos or a media player with video or audio. Users on Twitter can click on a tweet and expand it to see a picture without leaving their feeds.

The decision comes after Twitter earlier this year disabled a feature that let Instagram users look through Twitter accounts to find possible friends for the photo-sharing service.

At the LeWeb technology conference in Paris today, Systrom apologized for the confusion around the decision on Twitter cards. He said the move wasn’t a consequence of the acquisition by Facebook, and was his decision.

Instagram users will still be able to post messages to Twitter from the mobile-sharing service, Systrom said in the statement.
“We will continue to evaluate how to improve the experience with Twitter and Instagram photos,” he said.