Amazon has quietly launched a service for printing photos and custom photo books, in a direct challenge to companies like Shutterfly. The service, known as Amazon Prints, is available to customers who use the Amazon Drive cloud storage service, with free shipping on orders of $15 or more. The company also discontinued its Unlimited Photos storage plan this week. The service, which was previously available for $12 a year, is no longer available on Amazon's website; users who had paid for it have been offered to sign up for Amazon's unlimited storage plan, which costs $60 a year, according to customer emails that the company sent out this week.

With Amazon Prints, users can print photos starting at $0.09 each, and photo books starting at $20. According to the company's website, stationery and calendars will be available to print, as well. Users will only be able to print photos that are stored on Amazon Drive, however, and the service is only available to customers in the US who use Amazon Drive or Prime Photos. Following news of the launch, Shutterfly's stock fell by 12 percent, Bloomberg reports, marking the company's biggest single-day plunge since 2008.

Those who had paid for Amazon's Unlimited Photos plan have been offered free trials for unlimited storage, according to customer service emails. As PetaPixel reports, some have been offered three month trials, while others have been offered 12 months. It is not clear what will happen to the data of those who decide not to sign up for the higher priced plan. Prime Photos also offers unlimited storage, but is only available to Amazon Prime subscribers.