If you ever need to take a screenshot of an application or screen on your HTC EVO 4G LTE, there are two methods you can use. The first and older-style method is to press and hold power and then tap the home button. The screen will flash and a copy of your screenshot will be saved in the DCIM folder on your internal memory.
A different method which works with the newer EVO/some ICS ROMs is to press power and volume down at the same time and hold them for about one second until you see an animation that the image was captured. The screenshot will be produced the same, the animation will differ slightly letting you know it was taken, and the image will be placed in the Pictures\Screenshots folder. After the screenshot is taken you’ll receive a notification in the drop down section that there’s a screenshot available to view which you can view in the default gallery or any other image viewing application you have installed.
Both of these methods require some timing. If you don’t press home on the first method within two seconds the power menu will pop up, and if you release power or volume on the second method before the screenshot is taken you’ll either lock the phone or turn the volume down. Fortunately neither of these does anything other than make your screenshot fail.
Now go grab some screens!