“Presenting Evidence”

Can I present evidence when I'm cross examining the police officer? For example can I ask the police officer whether the road was straight or on a curve and if the officer answers wrong then pull out a picture to hurt his credibility?

You can ask the officer any questions that are material and relevant to the issues being tried. If you intend to contradict the officer later about something they said in their examination in chief, you MUST question them about it. This is known as the Rule in Brown V Dunn. What you can't do is lead evidence of your own during the cross examination of the officer. If you want to lead evidence of your own (whether it contradicts something the officer said or not), you do that during your own case in chief (after the crown closes).

Doing cross examination properly and ethically can be tricky. I'd suggest you consult a lawyer or paralegal if you anticipate issues coming up. What I've said in the paragraph above is not legal advice and is not enough on its own for you to go out there and cross examine an officer adequately.