(CNN) -- Users of Instagram, the popular photo-sharing app owned by Facebook, were up in arms Tuesday over language that appears to give the company ownership of their images.
A new update to Instagram's terms of service states that data collected through the app can be shared with Facebook. That's not a surprising move, considering Facebook paid an estimated $1 billion for the photo-sharing service earlier this year.
But the language that's upsetting some of the app's more than 100 million users says that "a business or other entity may pay" Instagram for the use of user images and may do so "without any compensation to you."
That didn't sit well with some -- including Facebook CEO Mark Zuckerberg's wedding photographer.
Kalina stopped short of vowing to quit Instagram, saying he hopes that language will be deleted. The proposed changes are set to go into effect January 16.
Others weren't being so patient.
A popular Twitter feed associated with the hacker collective Anonymous was urging its more than 780,000 followers to dump the app Tuesday morning.
"Only way to opt out of @instagram selling your photos is deleting your account," wrote the person who runs the account. "Sounds good to us. #BoycottInstagram".
The feed posted image after image of screen shots from followers who had done just that. It claimed it was receiving thousands of such images -- too many to count.
The new terms would significantly broaden what Instagram can do with users' content. Currently they say, "Instagram may place such advertising and promotions on the Instagram Services or on, about, or in conjunction with your Content."
Wil Wheaton, who parlayed a child-actor stint on "Star Trek: The Next Generation" into becoming one of the Web's earliest star bloggers, wrote that he doesn't use Instagram. But he questions whether other "celebrities to some degree" could be exploited if they do.
"If someone Instagrams a photo of Seth Green walking through an Urban Outfitters, does that mean Urban Outfitters can take that image and use it to create an implied endorsement by Seth?" Wheaton wrote. "What if the picture is taken by a complete stranger? Who gets final say in how the image is used? The subject, the photographer, or Instagram?"
Even CNN's own Anderson Cooper was expressing some concern on the site.
"#Instagram will now be able to use anyone's photos in ads? Without consent?" he wrote on Twitter. "Come on! Is there another photo app people recommend?"
Cooper isn't the only one considering his options.
Bloggers are spotlighting tools like Hipstamatic and Camera Awesome, as well as Twitter's own new photo service that includes Instagram-like filters.
A year-and-a-half-old blog post from photo-sharing site Flickr was also making the rounds. In it, Yahoo, which owns Flickr, uses language, perhaps aimed at Facebook, that says "(w)e feel very strongly that sharing online shouldn't mean giving up rights to your photos."
Facebook did not immediately return a message seeking comment for this story.
It is, of course, too early to know how many people are fleeing Instagram. But anecdotal evidence suggests a movement is afoot.
Instaport, a tool that lets users export and and download their Instagram images, was reporting overtaxed servers Tuesday morning.
"Our servers are very busy right now, so it may show you some errors," the company wrote to a user on its Twitter feed. "Please try again later or tomorrow."