Caroline's father, John, who has been highly critical of the police operation, said that he believed that his daughter's killer was still in the area.
Caroline, 13, was raped and murdered in a tiny shared hostel dormitory in Pleine Fougeres, Brittany, while on a trip with Launceston Community College from Cornwall.
The photo image was compiled with the help of some of Caroline's fellow pupils when French detectives visited Launceston earlier this month. The pupils and a teacher are believed to have spotted a man acting suspiciously around the French hostel.
Mr Dickinson, 41, from Bodmin, Cornwall, made his eighth trip to France to attend the police news conference, where the photofit was released.
He said he believed Caroline's killer was "still in the region and keeping low, because until now no one has known what he looked like, and he has felt able to relax himself".
"But he is going to be found out soon because people will recognise this photofit, I am very, very confident about it," Mr Dickinson added.
The photofit was "the sort of face that I am sure will have stuck in people's minds, even though he may have changed his looks from that time", he said.
Mr Dickinson made a personal appeal to the French public for information, and asked them to look "long and hard" at the photofit and come forward if they recognised the man. He dismissed "negative comments" that there was little chance of finding the culprit - even with a photofit.
"That is not my personal feeling. I think it is a very important new development, and I am sure people will have their memories jogged and come forward," he said.
"It could have been anybody's daughter," said Mr Dickinson, who felt the net was "drawing in" in the search for the killer.
The photofit will be distributed to police stations, petrol stations and post offices across France.
Earlier this week it emerged that the cotton wool gag used to smother Caroline came from another hostel 25 miles away - where another British schoolgirl from Salford, Greater Manchester,was attacked earlier that night in July 1996.
But the vital link was only made when the investigation was last year handed over to Judge Renaud van Ruymbeke, who replaced Gerard Zaug, the original investigating magistrate, after criticism from the Dickinson family.
The "intimate knowledge" of the two hostels and possible earlier intrusions at other hostels pointed to someone from the Brittany area being the culprit, said Mr Dickinson.
He claimed that the cotton wool was one factor linking the two attacks and the previous failure to establish that showed Mr Zaug to be "incompetent".
Meanwhile, Mr Dickenson's MP, Paul Tyler, the Liberal Democrat for North Cornwall, renewed a plea to the Foreign Office for both the British and the French authorities to learn the lessons of the murder.
Both he and the Dickinson family urged the need for Europe-wide standard security arrangements in all hostels for young people, and pointed out weaknesses in the translation arrangements, and the extra difficulties caused by the different police and judicial systems.
Delays, an information blackout, "casual incompetence and a cavalier attitude were the hallmark of the initial investigation," said Mr Tyler.
"Evidence which should have been pursued vigorously in the first 18 days has remained unchecked for 18 months," he added.