A police diving team will soon do preliminary work at the spot where officials believe the picture was taken, spokeswoman Ann Angela said.
It is too early to say whether the tip is more viable than the other numerous ones authorities have received, Angela said.
"It could be a skull, it could be a stone, it could be anything," she said. "That's what we're trying to figure out."
The couple cannot pinpoint the exact location, but a local resident believes he can find the spot, Angela said.
"We are a very small island with lots of people diving or snorkeling, so it's not unusual for one of us to see an underwater picture and recognize the location."
Angela said she could not reveal where or when the dive would take place so as not to attract onlookers.
On Thursday, a newspaper in Pennsylvania reported that a photo taken last fall by the visiting couple, John and Patti Muldowney, of Manheim, Pa., had been turned over to the FBI.
No one answered calls Saturday to a telephone number listed for the couple.
The search is one of many that authorities have launched to find Holloway's body since the Mountain Brook, Alabama, teen disappeared while on vacation in Aruba in 2005. The 18-year-old was last seen leaving a bar with Joran van der Sloot on the final night of a high school graduation trip.
Van der Sloot has been detained several times as police continue to investigate the case.
A Dutch TV station recently aired a paid interview in which van der Sloot claims Holloway accidentally fell from a balcony and that he disposed of her body in a swamp.
He had previously told an undercover reporter that she died unexpectedly while they were kissing and he dumped her body in the ocean.
Aruban prosecutors say they lack evidence to charge van der Sloot.
