ALBANY, N.Y. — Alice Connors-Kellgren was surprised by her boyfriend's new Facebook profile picture a few weeks ago: He was kissing another girl on the cheek.

The picture was up only briefly. And she figures it was just a friend. But she plans to discuss it with him when they're back together this fall at Cornell University.

"We trust each other. Deep down, I know nothing is going on. But when you first see it, it's like 'Oh my goodness! What's going on here?'" says the college student from Westchester County, N.Y.

All this friending, poking and picture-posting on Facebook can get you in trouble with your significant other. Couples are finding that old flames and flirty friends on the social networking site have a unique ability to stir jealousy and suspicion.

Jealous types now have to deal with brand-new kinds of provocations, such as a comment on their partner's wall from a possible romantic rival, or their loved one getting tagged — identified — in a picture from an old relationship. Boyfriends and girlfriends can view all of this on their partners' walls.

"It seems like Facebook is creating jealousy even where there was not jealousy to begin with," said Amy Muise, a doctoral candidate at the University of Guelph's psychology department who led a recent study on how Facebook can spark jealousy in romantic relationships among college students.

She said Facebook doesn't necessarily make people more jealous than they would be normally. But all the information divulged on Facebook — those answers to "What's on your mind?" and reactions to those posts — can increase "triggers" for jealousy.

"Part of the issue with information on Facebook is that it lacks certain context, " Muise said, "so there could be things posted on your partner's wall that you really don't know what it means."

The study was based on anonymous online survey data from 308 undergraduate Facebook users, three quarters of them women. The study, published in CyberPsychology & Behavior, found Facebook users can get snagged in a "feedback loop": Their interest piqued by a cryptic wall comment, they become suspicious and start monitoring their partner's pages, thus finding even more suspicious information.

Dan Fitzsimmons, a 21-year-old University at Albany student, said he has had to explain Facebook photos to girlfriends in the past.

Samantha Siciliano, an incoming freshman at Quinnipiac University from North Adams, Mass., said she has become jealous over the back-and-forth on her old boyfriend's wall, especially from too-friendly comments like "You look cute."

"If your boyfriend is calling or texting another girl, you can't really see it. But on Facebook, you can see it and so can everyone else," Siciliano said. "So in a way, you do get jealous because he might be hanging his dirty laundry, and not only are you seeing it, but other people are, too."

Colin Booth of West Virginia University said he is not the jealous type, but finds it a strange, modern phenomenon to watch your girlfriend develop other relationships in real time on Facebook.

"It's been happening forever. You're with a girl, she meets a guy, they're friends at first," Booth said. "But it's the way you see it and what you see. And then you think: What's going on under the surface if this is what's going on in public?"

Laney Cohen, a 24-year-old who works in public relations in New York City, has a longtime boyfriend now in law school in Florida. She began noticing last year that her boyfriend was being tagged in photographs with a female friend who "kind of rubs me the wrong way." One picture in particular upset her: The pair were in a bar, and the woman was looking up at Cohen's boyfriend.

"I felt that it was a very couple-y picture to be in, and I freaked out and I called him and said, 'This is disrespectful to me and our relationship. What if people start asking questions about why you're always hanging out with her?'" Cohen recalled.

This is not just a problem for young people, especially as more middle-aged people get on Facebook. Cohen said her father, after 29 years of marriage, was tagged in a 32-year-old photo by a former girlfriend. Cohen's mother was amused, not upset.

Muise said researchers are just beginning to learn all the ways social networking sites are changing the way couples relate. She cited the case of a young woman who found out her boyfriend broke up with her when she noticed he had changed his relationship status to "single."

For her part, Cohen said she and her boyfriend worked out their photo-tagging issue.

"He's either untagging photos or not showing up in the photos anymore," she said. "Either way is fine."