Quickly capture screens and share them on OS X with Skitch
Macs don’t have a PrintScreen button, and if we want to take a screen-capture, the default program we use is Grab. Grab is great in a few ways; you can choose to use a timer before a screen-capture is taken and it can be used to ensure only a certain area of the screen is captured. Unfortunately, after a screen capture has been taken, Grab lacks any features to edit it (eg cropping) and only lets you save it as a TIFF.
It can be somewhat cumbersome to capture a screenshot in Grab, and then have to move it into a program like Photoshop to manipulate it. And if you want to share the image, you have to change its format.
An alternative piece of software is
Skitch, screen-capturing software for OS X. Skitch provides screen-capturing facilities similar to Grub, but integrates some editing tools and also provides tools to share the images