If the photo had fingerprints other than that of the person who had found it and anyone who had handled it afterwards, and if the police tried to find fingerprints, then I doubt they would have been able to identify them as it is not likely they would have been in any database (as I doubt the person or persons they belonged to had ever been fingerprinted).
To recapitulate:
1) The scene looks entirely staged. There are no actual restraints showing on either of the victims. The girls arms are positioned in such a manner as to make it most doubtful that her hands are even crossed behind her back. She seems to be acting a part in a rather disinterested and halfhearted manner, unlike the boy in the photo, who is probably her kid brother. Being both a boy and a younger child, he was likely more into the joke photo than her, which was probably taken by another kid, most likely their brother. Thus, his more convincing performance.
2) As Carl pointed out, the gags (tape) are applied ineffectually.
3) There is a book and other objects lying on the bed which indicates no sign of a struggle. If the victims were cowed by their abductor(s) into passively allowing themselves to be bound, then why the need for gags or, for that matter, the (inferred) bonds? If shortly before the photo had been taken the girl had been reading the book on the bed, it seems most unlikely she had been doing so with her hands free while wearing tape across her mouth. In this scenario, why would an abductor suddenly decide to bind and gag the kids and take such a photo? There was apparently no record of such a photo being sent to the family or families of the victims as ransom demands and no record of such a kidnapping for ransom at all.
4) The presence of a book on the bed that would appeal to a young woman of this age suggests that shortly before the photo was taken she had been reading it. Therefore, the photo was taken on an impromptu basis. This indicates a brainstorm by one of the participants, probably the kid who took the photo and who had seen a roll of tape lying about. He convinced his kid brother and his (probably) older sister to go along; in the latter case, probably reluctantly to placate him as she had been older and more mature.
5) Since there is no record of a ransom demand fitting these subjects descriptions, then the only other motive for such an abduction that comes to mind is sexual. Regarding the only two proven cases that I know of where a pedophile had held two kidswho hadnt known each other beforehandsimultaneously against their wills, both involved kidnappings years apart when the pedophiles had wanted younger kids to replace their original victims who had outgrown their abductors' perverted sexual tastes. It would also be rare for a pedophile to have abducted children of both sexes.
6) It seems far more likely that kids engaged in a prank would either intentionally or carelessly leave such a photo in a public place than would one or more pedophiles who have successfully kidnapped youngsters and eluded police in the process. Since the town where the photo was found was one in Florida that attracts a lot of vacationers and tourists; and since the photo was found on June 15th, a week or so after many schools would have let out for the summer, it is reasonable to infer that the kids involved in such a stunt had been vacationers (with their parents) in the town rather than residents. Thus, they would not have feared being recognized by locals. (The kids might not even have been Americans.) The photo was most likely taken in a motel room while the parents were out for the evening (a likely time for the older child to have been reading a book while watching her younger siblings).
Against all of this logic, the case that the photo was a genuine abduction shot rests on the facts that the girl resembles a missing young woman (whom, by the way, at age 19 was older than the age this girl is judged to be by the FBI) and that the boy (whose speculated identity has been all over the place) in particular looks terrified.
Draw your own conclusions.
Respectfully, these are my conclusions:
1. Few people actually KNOW what a person would look like if they were in such a situation. Therefore, I think that we can't really say how one would "look" if they were in this position, especially children and young adults. And, if these children had been abused or threatened previously to these photos, they might well be restrained just through pure fear. Remember that Richard Speck was able to "restrain", rape, torture and kill 8 nurses back in 1966. There are numerous cases of killers being able to control and restrain people just by their fear. Maybe the girls hands were tied or maybe they weren't tied at all and he told her to put them behind her back while he took the photo? I don't think that we can infer anything by the expressions on their face. Everyone will see something different. You see boredom and acting, I see defiance and terror.
2. Again, the gags may also be part of the killer staging this photo for impact to the public. What better way to say to the world that these children are gone and he has them? He may have them somewhere that he is not concerned about them yelling and anyone hearing them. We can't see their feet. Perhaps the feet are tied or chained and he knows they can't go anywhere.
3. There appears to be bedding thrown down for the kids to lay on. Some think that it is in the back of a van, but I wonder about this because of the lamp up in the left hand corner that appears to be sitting on something. Maybe a camper that has a table? I don't think from this scene that one can infer that there appears to not have had a struggle. It doesn't necessarily look like there was, but in such a small space, what would a struggle look like? The girls hair is messed up. Again, the book laying there does not necessarily mean that she was reading it before or after the photo. If the killer abducted these kids and wanted to play a horrible game by leaving pictures around, he might have left the book there as a prominent clue as to who the girl was. I think the book was placed there as a clue just like the photo was placed in the parking lot.
4. Completely conjecture in the theory that this was set up. This is all subjective. To you, the scene looks like the girl had been reading the book. That would be the obvious thought. And, you have said that you believe this scene was staged by the middle brother. How do you get to that conclusion?
5. Just because you don't know of a case where 2 people were kidnapped separately does not mean that it has never happened. Sex isn't the only motivation for kidnapping. There is human trafficking as well. Perhaps the person had one longer than the other. Perhaps he thought he wanted a girl but decided that he wanted a little boy too. Perhaps he was working with a group and was taking them back to the group for whatever reason and decided to take this photo to either terrorize the community or maybe someone made him do it and he was trying to leave a clue? There are dozens of scenarios and most of us can't get our head inside of it because we are normal, sane individuals. I personally will never be able to think in the way a person like this would think, and I'm grateful for that.
6. Pure conjecture and you are trying to make the scene fit your beliefs. It is jumping to a lot of conclusions about the photo. Remember that this photo was taken with a film camera. It would have had to been developed and printed (unless the supposed middle brother had a dark room). It just doesn't seem to me to be something that a kid could/would do. And, what of the places that developed the film? Wouldn't this photo draw attention? Wouldn't the person who left it worry that they would be caught?
I believe that this photo is of Tara Calico. That's not only my belief, it's the belief of many thousands of others, including her own mother. I don't know who the boy is as he is further back in the photo and can't be as clearly seen. I am the mother of 5 daughters, so I can say with clear experience that 16 year olds can look 19 and vice versa. In the known photos of Tara, she looks young to me. Three years difference in a girls life is hardly a reason for the FBI to discount that this is her. It looks exactly like her and if I was her mother, I would be able to know positively that this was my daughter. The boy, on the other hand, is not as easy to identify.
As I said before, I respect your opinion, but I just wanted to point out the other side.