How do i access the material on a connected iPhone?

When i first got my computer (MacBook Pro) whenever i would plug in my iPhone, the iPhoto would open and ask if i wanted to sync my iphone. Now everytime i plug in my phone it opens but it doesn't ask to sync my photos and doesnt give me an option to. I dont know how to open and see the contents on my phone on my computer to copy and paste it either. Please help!