A day after Instagram caused widespread disquiet with its new terms of service, the photo-sharing app's CEO has attempted to reassure users that it has no intention of selling photos to advertisers.

Kevin Systrom, in an attempt to mend fences by explaining the changes in more detail said many users are "confused."

"It was interpreted by many that we were going to sell your photos to others without any compensation. This is not true," he said on the company's blog. "Let's say a business wanted to promote their account to gain more followers and Instagram was able to feature them in some way. In order to help make a more relevant and useful promotion, it would be helpful to see which of the people you follow also follow this business. In this way, some of the data you produce - like the actions you take (eg, following the account) and your profile photo - might show up if you are following this business."

Instagram, which Facebook bought in April for close to $1 billion, published its new terms of service earlier in the week, with a view to bringing them into effect on Jan. 16, 2013. In particular, users were concerned about the data Instagram says it plans to sell to advertisers.

"To help us deliver interesting paid or sponsored content or promotions, you agree that a business or other entity may pay us to display your username, likeness, photos (along with any associated metadata), and/or actions you take, in connection with paid or sponsored content or promotions, without any compensation to you," read Instagram's new terms of service.

Systrom explained that the changes were there simply to allow it to experiment with innovative advertising.

"The language we proposed also raised question about whether your photos can be part of an advertisement. We do not have plans for anything like this and because of that we're going to remove the language that raised the question," said Systrom. "Our main goal is to avoid things like advertising banners you see in other apps that would hurt the Instagram user experience. Instead, we want to create meaningful ways to help you discover new and interesting accounts and content while building a self-sustaining business at the same time."

On Tuesday, the Wall Street Journal reported several high profile celebrities deleting their accounts to protest Instagram's change of terms, which followed backlash from ordinary users on Twitter.

Additionally, the New York Times reports that several services that offer the ability to download all their Instagram photos, such as Instaport.Me and Instabackup, have seen increased activity. Presumably this is due to users saving their Instagram data before deleting their accounts.

"It's a thousand percent more activity than we're used to," Linus Ekenstam, who helped found a service called Copygram that lets people back up their Instagram accounts and order physical prints of their favorite photos, told the news site.