Just about every cell phone has a camera built into it nowadays, and it’s a feature that can come in handy after an accident. You may not be at fault for the incident but you never should rely on the offender being completely honest about what happened. Getting out your cell phone or smartphone and taking pictures afterwards, if at all possible, shows proof of who was where when the collision occurred.
It’s a good bet that you are going to have to defend yourself in the claim process even though you weren’t at fault. The offender’s insurance company is most likely be difficult about paying out money to cover your bills. Having pictures of the incident that shows the damage in situ makes it much harder for the offender’s insurer to quibble with you about what happened. After all, the only thing you’re looking for is the insurance company to do as it says it will and pay out on your claim. Having proof puts the ball in your court and leaves the insurer with less of an excuse to not take care of your request.