Capture only a portion of the screen! That sounds interesting! Snippy is a free screen capture that allows you to capture an area that you are going to define.

Disclaimer: it seems that the publisher's website is closed and that the software is no longer supported. Thus, even though the version linked to this page is the latest to exist, it may no longer work on your computer, or run with recurring error messages.

What are the key features of Snippy?

Capture: unlike other screenshot softwares Snippy determines the area to be captured on the screen. The screenshot will be sent to the clipboard. To do this, you must mark the screen with the mouse as a pen to draw the area (as seen in the picture). It is also comforting to know that the image quality is kept at 100%.
Possibility of saving: the screenshot can then be saved in the clipboard so that the user can later use them as they please. They can be stored in many image formats: PNG, BMP, JPEG, GIF, TIFF. It is also possible to copy (the captured image) directly in your inbox.
Customization: the "Settings" menu on the software’s interface allows you to customize capture modes. Indeed, by pressing the right click of the mouse, you can change the color or thickness of the felt for marking-out.