One of my first lessons of living the Android Life was figuring out how to take a screen shot. Sounds easy enough, but this became my first exposure to the differences between Apple and Android phone makers.
For all iOS devices, holding down the physical power and home buttons trigger a screen shot. For Android, taking a screen shot depends. Yes, it depends on your version of Android and the hardware of your phone. In general, the key combo for an Android screen shot is the power button and volume down held down for a bit, but again, it depends.
Then the screen shot isn’t necessarily saved to the standard “camera roll” as with iOS. The screen shot is copied to the internal clipboard and needs to be “pasted” somewhere. Android will prompt you to choose which app to store the captured screen shot, Google+ Pictures, the phone’s Gallery app, or others.
When emailing a screen shot (or any image for that fact), Apple Mail typically asks the user to resize the image before sending. Android though wants to send the full resolution, multi-megabyte image file. You’d need a third party app to resize the image on Android before emailing.