For many top-tier presidential candidates at Iowa's Polk County Democrats Steak Fry, the day began with a picturesque procession on to the event grounds. Some marched in with bands, and some strode in with hundreds of supporters, shirts and signs in tow.

Sen. Elizabeth Warren and her team, however, did not show up for the morning march photo opportunity. Instead, the procession came to their camp — in the form of the so-called selfie line.

For two hours, Warren greeted hundreds of fans and supporters here in Iowa as her mint-green adorned campaign workers and volunteers executed the selfie line logistics with deft precision — forming a line, holding people’s bags, snapping photos, and making post-photo requests for support in the February Democratic caucus. Some think the selfie line will help her continue her upward momentum.

“You don’t win Iowa without doing retail politics,” said Adam Wright, 41, who was sporting a button indicating February caucus support for Warren.

To Wright, the selfie line is one of the most clever things a politician can do in a state like Iowa, where people expect direct access to candidates.

“People put that on social media, other people see that, and also, too, it shows that a candidate is accessible,” he said.

Warren's campaign claimed she took slightly more than 1,000 photos Saturday. A spokesperson praised the technique as a way for the Massachusetts senator to connect with voters.

"As wasteful as it might seem, it can be an efficient use of time if you have the right exchange of pleasantries — the eye contact, the friendliness — with the prospective supporters.

Dennis Goldford, political science professor of Des Moines' Drake University, said there is no research on how selfies or photos impact voter behavior, but the photo opportunity is a chance to "make a sale" to undecided voters.

"There are a lot of people who are window shoppers — they may not be ready to buy yet — and they take advantage of events like the Iowa Steak Fry and others when they get to talk to candidates in-person, and maybe get a selfie with them, to get a little closer to making a decision as to which one they're going to buy," said Goldford.

But a picture doesn't always ensure support.

Brandon Harrison and his infant daughter Elena were among those who waited in line for a photo with Warren. They took a picture with the Massachusetts senator while Harrison wore a daffodil-colored shirt with South Bend, Indiana Mayor Pete Buttigieg's name on it.

"They're both in my top three. I'm still kind of undecided," Harrison affirmed after taking his picture. "It's a little more complicated than just making up your mind before a primary, which is kinda what makes a caucus unique."

Having multiple top choices is not uncommon in the first-in-the-nation contest state where the caucus process includes a viability threshold. If a candidate doesn't have enough support during a caucus, she is declared "not viable," and her supporters are asked to join another, viable candidate's camp.

Harrison said he typically solidifies his top choice around the holidays, but with such a large candidate field this year, he may enter February's caucus undecided.

Meanwhile, Wright has pledged to support Warren in the caucus and says her photo effort reminds him of Barack Obama drumming up support here in Iowa ahead of the 2008 election.

“He went to the coffee shops, he went to the breakfast places, he did rallies in high school gyms, and he got out there in the backyard events and got to meet and got to know caucus goers one-by-one," Wright said of Obama. "So, this is a very smart strategy on [Warren's] part.”

For now, the photo line strategy appears to be paying off. The Des Moines Register’s latest poll shows Warren as the front-runner among likely Democratic voters.

But that poll is just a narrowly-focused snapshot, and with roughly four months left before the Iowa caucuses, the picture of Warren and her selfie-line strategy could change.