The U.S. Federal Trade Commission should investigate Apple and Google for allowing applications on their mobile OSes to access users' photographs without permission, a U.S. senator said.

Some mobile applications on the Android and iOS OSes "steal" users photos, said Senator Charles Schumer, a New York Democrat. The mobile OSes allowing apps to access user photos is a "disturbing and potentially unfair practice," Schumer said in a statement issued Sunday. The New York Times reported on the issue last week.

"When someone takes a private photo, on a private cell phone, it should remain just that: private," Schumer said in a statement. "Smartphone developers have an obligation to protect the private content of their users and not allow them to be veritable treasure troves of private, personal information that can then be uploaded and distributed without the consumer's consent."

By accessing user photos, the mobile apps go beyond users' reasonable expectations what information apps need to function, Schumer said. It appears that apps accessing photos violate the Apple and Google terms of service, he said.

"However, it is not clear whether or how those terms of service are being enforced and monitored," he wrote in a letter to the FTC. "In fact, the abuses of apps have only come to light as a result of the work of intrepid independent researchers and technologists.A As a result, it is users and their privacy who suffer."

Google, in a statement, said it is reviewing its policy on apps and photos. The company designed the Android photo file system similar to the ones in Windows and Mac OS, and images were stored on SD (Secure Digital) cards, allowing users to remove the cards and transfer pictures to another device, the company said.

"As phones and tablets have evolved to rely more on built-in, non-removable memory, we're taking another look at this and considering adding a permission for apps to access images," Google said in its statement. "We've always had policies in place to remove any apps on Android Market that improperly access your data."

Apple did not respond to a request for comments.