The move shows the growing rivalry between Twitter and Instagram, which was bought by Facebook earlier this year. By disabling Twitter cards, Instagram will force Twitter users to click through to its site to see the entire image.
Social networks are growing increasingly protective of their platforms as competition rises for users and for advertising revenue. Twitter has, in recent months, tightened its rules on what third-party applications are able to do, in a move that his been interpreted by some observers as an attempt to keep users on its platform.