SnapCrab is a program that can capture any part of your computer´s screen.
When installed, it puts a tiny icon in your system tray. If you click on it, a small toolbar will be displayed giving you access to all the program functions.
You can use this program to capture the active window, or another window selected by you. It can also capture the full screen, or just the region of the screen. All the captures will be saved in the PNG format, in the Desktop folder, by default. But you can set the program to use the JPG or GIF format, and choose whichever folder you want.
SnapCrab allows to send the captures you take automatically to your Twitter, Facebook or Evernote account. It will ask you for your username and password when you use this option for the first time. In Facebook, you will have to authorize SnapCrab to post images on your behalf.
The program also features a Color Picker, a utility that will let you copy just a color of the screen, allowing you to use that color in other images, or to fill the background on the images that you capture. You will be able to define hotkeys to perform each action that the program can take.