In other words, you think that they didn't release the video because they have something to prove. I think that they didn't bother because they have couple overworked clerks and hundred cases just like this — regardless of whether the video proves innocence or guilt. I honestly don't see this case as important enough for any officials involved to have any special motives or do anything other than bare minimum required.
Really what I'm saying is that if I'm going to try to extrapolate something more from the information presented that would be the direction, not "Can we be sure he hasn't faked this picture?". My point is that you're speculating that someone is guilty despite a strong piece of neutral information: the DA dropped the case and he was released from jail.
Sure, it's possible the attorney faked the picture and it's all bullshit, but there's nothing to demonstrate that as being likely besides your own biases.
>...the only thing worth questioning here is if that shot is in fact real–something that could only be evaluated if they released the tape. But since they're not exactly going out of their way to do that I can only assume that it would be against their interests.
The police and prosecution have the latitude to release that video and could certainly do so to exonerate themselves. Releasing it is what the police should have done immediately after his case was dropped if their interest was is in catching a robber on the loose or demonstrating publicly that they did have the right man and the prosecution was dropping the ball.