A recent e-mail from Eastman Kodak Co. didn’t lead to a Kodak moment for Vanessa Daniele. It got her angry.

On May 16, the company’s Kodak Gallery online photo service will delete her picture albums unless she spends at least $4.99 by then and every year thereafter on prints and other products.

That’s the new rule for people whose photos take up less than 2 gigabytes of space on Kodak’s servers — enough for around 2,000 1-megabyte photos. People over that limit must spend at least $19.99 a year. And customers who signed up under the old rules won’t be given a pass.

“I don’t ever think it’s a good idea to change terms of service on customers after they’ve signed up, and demand a new storage fee or threaten deletion of photos,” said Daniele, 26, who lives in Chicago. “That action doesn’t value the customer or attract new ones.”

Kodak Gallery, once known as Ofoto, said it wants to focus on its best customers, not folks who merely want to take advantage of free picture storage. And its new rules are hardly unusual in the online photo business.

But the company’s decision to change its policies illustrates the risks people face as they increasingly rely on privately run services to handle their digital memories and communications. These services often state in the fine print that they can change the rules at any time, and users have little recourse when they do.

Many online photo services offer free storage of images as a way to lure customers who might buy prints or things like mugs with pictures imprinted on them. One such site, Hewlett-Packard Co.’s Snapfish, offers unlimited storage to users who make an annual purchase of any amount.

These sites typically store users’ original, high-resolution files on their servers, and display lower-resolution versions that are fine for Web viewing but might not be clear enough for good prints. So users who fail to keep copies of their original picture files might have no way to get them back from a Web site unless they pay extra for the service.

Kodak, for instance, charges $9.95 to send users 50 of their photos back on a CD, or $39.95 for up to 1,000 photos. Every additional 1,000 images costs $14.95.

Daniele’s situation is complicated because the albums she organized and stored at Kodak Gallery are made up of pictures taken by friends and family and uploaded to the site by them. She doesn’t have copies stored elsewhere. Now those images would be deleted even if she makes purchases above the site’s new minimum but her friends and family don’t.

That means she’ll have to upgrade to a $24.99-a-year premium account to download high-resolution versions of the images, or spend $19.95 plus shipping if she wants to have Kodak give her the 200 pictures on a CD, so she can upload them to another photo site.

Kodak is essentially saying that “even though you own this stuff, unless you pay us you’re going to lose your access to it. That hardly seems fair,” said Steve Jones, a communications professor specializing in new media at the University of Illinois at Chicago.

Kodak said it has required an annual purchase for the past five years without setting a minimum amount. The new policy, adopted in March and announced in recent e-mail notices, sets a minimum.

“For folks who have been using us just for free storage, they may decide they just want to make a small purchase,” said Mark Cook, director of product marketing at Kodak Gallery. “Or, they may decide to leave.”

Cook said Kodak is still adding value for consumers: This month, it began offering free shipping for people buying at least $5 worth of pictures in most sizes, as an added incentive to purchase more prints.

Other photo sites, including Google Inc.’s Picasa, Fotki Inc., Yahoo Inc.’s Flickr, News Corp.’s Photobucket and Adobe Systems Inc.’s Photoshop.com still offer free services that let people share photos with others, although there are storage limits. You can buy additional storage or upgrade to a paid account for unlimited uploads.

Even more generous options are available at Shutterfly Inc., which offers free, unlimited photo storage, and on social-networking sites such as Facebook, which doesn’t have a limit.

But it’s not unusual for photo-sharing sites to start out free and then require payment, such as a now-defunct service from Sony Corp., said Terry Sullivan, associate editor of digital imaging at Consumer Reports magazine.

Sony closed ImageStation in 2008 to focus on its core business, nearly eight years after launching the photo-sharing site. Sony said it has destroyed all images left on its servers.

Time Warner Inc.’s AOL ended its photo-storage site in January to cut costs. It transferred images to American Greetings Corp.’s PhotoWorks, which requires an annual purchase or else photos will be deleted.

Given all the varying policies, it’s best to back up your pictures on your own computer. That should greatly reduce the chance you’ll lose something irreplaceable.