Bring the pictures and if at all possible the picture taker as a witness to the place, time of day, weather conditions, and distances. Make sure the pictures are numbered and have these details noted on the reverse with the signature of the picture taker.
In court, you want to have the picture taker available to testify as to how the pictures match the conditions at the place and time of the ticket.
Your point is to show that the officer, from where he was, could easily have been mistaken as to what he saw. If the officer shows and takes the stand, try to get him to admit that, in the circumstances, he might possibly have been mistaken in the brief moment that he had to assess whether you were wearing your seat belt.
If the officer is a fool, he will insist that he could not have been mistaken. The most that he can honestly say is that he does not believe he made a mistake.
In addition, bring your minor witnesses. They can usually testify if over the age of seven or eight. You should be ready with a short and simple written list of questions that you want to ask them. You might offer or ask that the judge pose the questions in order to give a greater assurance that the children are speaking truthfully.
The key point is that with minor children aboard, as a standard practice, you insist that the children wear their seat belts -- and you always do so as well to set a good example.
I will, it says I have to appear just to request trial, then come back a second time.