For thousands of foster children, the search for a permanent family is framed by a display in the “heart gallery,” an annual showcase where heartwarming pictures of smiling, laughing and frolicking children beckon to prospective parents.

But A.B., a 16-year-old foster child from Jacksonville, was being sold with an entirely different set of photos. She wore high heels, a black skirt and a tight tank top that showed off her cleavage.

The caption for A.B.’s picture: “Experience me to know I will be your best!”

An ad in Backpage.com gushed that the girl’s “hands will be your best asset,” and added “$100 gift donation due upon arrival.”

The Backpage photos were a tawdry milestone in A.B.’s descent into prostitution — documented as part of the federal prosecution of her alleged pimp, Gregory Goellet Hodge Jr., who, authorities say, recruited the girl near the foster-care group home where she lived.

The case, which is still pending, shares eerie similarities to the arrest last week of four Miami-Dade men who, police say, recruited foster children from a group home to work at a Homestead brothel.

The girls caught up in the Miami prostitution ring share the same foster-care agency as A.B.: the Children’s Home Society of Florida.

Although the trafficking in underage girls into prostitution is not limited to kids in foster care, children’s advocates say such children are particularly attractive targets to pimps: They are separated from family, often poorly supervised, crave attention and affection, and often run away from caregivers to the streets.

“You would have to be naive to think that pimps do not realize this,” said Staca Shehan, director of case analysis for the National Center for Missing and Exploited Children in Virginia. “This class of minors are vulnerable. It’s not uncommon for foster children to run away. Once you run away, how do you support yourself? What do you do to find shelter and safety? What do you do to provide that for yourself?’’

The investigation into the underage prostitution of foster children in Miami continues.

State Attorney Katherine Fernández Rundle said last week that her agency, together with police, intended to file additional charges in cases where men have lured young girls into the sex trade, and will vigorously pursue the girls’ clients.

Sources told The Miami Herald last week that judges at Miami-Dade’s Children’s Courthouse who preside over child-welfare cases were given lists of girls in their divisions who police believe had been trafficking victims. The lists named several teenagers in addition to the four identified by their initials in last week’s arrests.

Sources also told the newspaper that such trafficking was not limited to foster-care group homes operated by Children’s Home Society.

“These girls all had very tragic, complicated pasts,” said David Wilkins, secretary of the Department of Children & Families, which pays the group-home bills for foster children. “All these girls have seen the hard side of life.”

When asked what he would say to people concerned about two such cases in less than 12 months at CHS facilities, President/CEO David Bundy said he would point to the company’s years of experience and emphasize the troubled backgrounds of the teens they receive.