If you have a Mac computer with Photo Stream enabled on the iPhone and the Mac, your photos will automatically be available in the Photos on the Mac. Through iCloud, your photos are automatically shared across all your Apple devices.
There are several ways to transfer photos from your iPhone to a Windows PC. You could use iTunes to transfer the photos when you sync your iPhone, but there is an easier way than trying to understand the iTunes sync process.
1. Connect your iPhone to the PC without iTunes running and wait for a popup asking you what you want to do with the device.
2. Select “View Content”, locate your photos on your iPhone, and copy them to the desired location on your PC.
3. If you don’t see a popup window after connecting your iPhone, open “My Computer” and locate your iPhone in the window.
4. Open the iPhone to find your photos and copy them to the desired location on your PC.
Additionally, if you have a digital camera, whatever software you use to get pictures off your camera will likely work with the iPhone too.
This article from the Apple website provides additional details.