In OS X it is very easy to capture the screen as an image. It also offers many options, and using the Preview, you can edit the capture in seconds. But those who want something more, Monosnap is a great option, a screen full of options and surprises for everyone.
Grabber OS X improved
Monosnap is a screen that allows a screen image or a particular area. In the second case, it shows you the pixel size using a magnifying glass, very useful to define the area to capture.
But Monosnap offers more. Also it allows you to record a video of what you see on the desktop, useful for creating screencasts with tutorials.
Third, Monosnap captures what appears in front of the camera on your Mac as a autofoto (or as is being called, selfie).