How to Capture a Screenshot on Your iPhone
One feature on the iPhone that is not well known is the ability to capture screenshots of any screen on the device. Application screens, gaming screens and system screens are examples of screenshots you can take. This feature is also useful if you take a screenshot of a system problem as it is happening, which can help you to find the best solution. The screenshot is treated like every other photo on the iPhone and can be emailed, used as wallpaper or assigned to a contact.
Go to the screen you want to take a screenshot of. For example, if you want to take a screenshot of an email, tap the "Email" icon, then tap the email you want to take a screenshot of to open it.
Press the "Power" and "Home" buttons simultaneously. A flash of the screen occurs that confirms the screenshot was taken.
Press the "Home" button to return to the home screen. Tap the "Photos" application to open it.
Tap "Camera Roll" and the screenshot will be displayed in the album along with the other pictures. Tap the screenshot to view the full-screen image.