Instagram move affects Twitter photo display on platforms
Instagram has removed support for a feature on Twitter that ensures photos are properly displayed on the site.
Twitter's cards feature meant pictures were uncropped as part of a tweet, but now some users say certain images are being cut off.
Instagram's chief executive, Kevin Systrom, said the move was to push people towards the firm's own website to give "the best experience".
The photo service was bought by Facebook in April 2012.
In a statement, Systrom said they had supported Twitter cards when Instagram had a "minimal web presence", but that it had now improved its website.
"[Users can] engage with Instagram content through likes, comments and hashtags," said the Instagram boss.
"Now we believe the best experience is for us to link back to where the content lives."
Users can still share on Twitter but in some circumstances photos appear cropped and miss out the edges of the image.
On certain platforms, such as Android phones, there is no preview at all, just a text link to the Instagram site.
Speaking at this week's LeWeb conference in Paris, Kevin Systrom denied the change had anything to do with Facebook's $1bn (£620 million) purchase of Instagram.
There's been speculation about tensions between the two companies after Twitter disabled the "find my Twitter friends" feature on Instagram in the summer.
Twitter is also said to be working on its own photo service in a similar style to Instagram.
The photo service, which now has more than 100 million users, allows users to apply various style and colour filters to their pictures.
Jamal Edwards, founder of hit music and lifestyle site SBTV, said he had personally experienced some problems with how the two services integrate.
"I was @'ing someone on Instagram and it didn't come up on Twitter properly.
"Then on the Rihanna tour I wanted to be the first one to post photos, but every time I tried to @ Rihanna it took it off."
He thinks Instagram and Twitter should work more closely for the good of their users.
"They should join up," he said. "Why are they going to go against each other?
"It's not going to affect any of the companies. It's going to affect the people using it and it's wrong."