Your reasoning assumes that if the shroud were genuine, then the energy that was used to impress the image would have radiated in all directions from Christ's body, leaving behind an image that looks quite different from one that resembles a photograph taken from some distance.
However, there is no basis to assume that.... if the shroud were genuine and the image actually formed at the moment of Christ's resurrection, the energies released during the event, at least insomuch as we would be able to discern the manifestation of it, could easily have have been entirely unidirectional, thereby producing an image more consistent with that of a photo,. like what is on the shroud.
And of course, the image doesn't even correspond with what most contemporary images of Jesus were portrayed to look like at the time of the shroud's alleged mideval manufacture.... it was common at the time to portray Christ's wounds as being in the center of his palms, and not at end of the wrists, as the shroud depicts. If it really was done by a forger, it was done by someone who had somehow figured out how crucifixion with nails was actually practiced, and was even more interested in being attentive to those details and scientific accuracy than in even being widely believed, since most people at the time would not have identified with the wounds being in the location where they were depicted on the shroud.
Sure, it's still possible that it was created by a charlatan, but how, and why? Particularly since nobody would have believed him in his lifetime anyways because it didn't conform to the common perception of Jesus. Assuming, of course, they could even see the image at all (since the image is all but completely invisible to the unaided eye).