I was confused about how I did it.
Last night (November 11, 2010), I accidentally figured it out.
Well, it all started by the hung/frozen iPhone. When I met my elementary schoolmate Joseph Cheng (鄭子碩) in September, my iPhone froze and I couldn't do anything, not even shutting it down. Joseph then told me how to do a hard reset/restart. Instead of pressing on "sleep/wake" button for a few seconds (normal shut down procedure), I had to press and hold "sleep/wake" button and press and hold the "Home" button. After pressing and holding both buttons for a few seconds, the iPhone will eventually shut down. A restart will take a few minutes to come up.
When I was checking the "Time Map" application on iPhone, it froze again and I had to repeat the above method to restart my iPhone. It was sitting on the Apple icon for a long long time. I waited and lost the patience and wanted to do another hard reboot. When I pressed and held the "sleep/wake" button and the "Home" button, iPhone came back and it made a camera shutter sound and the screen flashed. I was curious about the behavior. Since it had a camera shutter sound, did it mean I just took a shot? I went to "Photos" and select the "Camera Roll" and found the screenshot was in the album.
I tried a few combination and found out the steps of taking screenshots on iPhone.
1. Press and hold "sleep/wake" button (not to exceed 1 to 2 seconds)
2. Press "Home" button
3. Release both buttons at the same time
4. The screen will flash and the screenshot will be saved in Camera Roll album
This is helpful when you want to share the application errors, game records, system configurations and so on with others.
Share with you.