It wasn't a similar photo, it was the same exact photo. And it's impossible that Sarah Connor would have been driving through the desert pregnant with John at that exact moment the photo was taken had she not already survived the attack by the T-800. She'd be a waitress. The only possible conclusion is that John Connor was always Reese's son. And that's just a huge plot hole that can't be logically resolved.
That theory would mean that Skynet would always develop time travel and that there was never a timeline in which Sarah Conner did not know that Judgement Day was coming. The reason Skynet sends a Terminator back in time is because John Conner leads the resistance to victory. By sending something back in time, there has to be an original timeline that is now altered, hence there has to be a 1984 timeline in which Kyle Reese and a Terminator did not show up. The fact that Judgement Day changes between T1 and T2 shows this. The remains of the terminator are found by Dyson and his company and are used to create Skynet at an earlier date. If John and Sarah Conner were ever successful in stopping Judgement Day and Skynet, John Conner would probably cease to exist. Essentially you have the Grandfather paradox, where if you kill your grandfather before he has fathered your dad, will you cease to exist. If John Conner, son of Kyle Reese, stops Judgement Day, there will never be a point in the future in which he sends Kyle back to protect Sarah, hence he will not have been conceived via Kyle.
The original timeline could involve Sarah getting pregnant from a one night stand and quiting her job and going to the desert thus leading to the picture.