Screenshot

Mac

1. OS X has screen capture keyboard shortcuts Shift + Control + Command + 3 (or 4) copies screen image (or selected portion) to clipboard. Alternative is using Grab utility to capture Window, Selection, Screen, OR Timed Screen. Then copy screen capture to clipboard. An O’Reilly webpage has screen capture examples.
2. Open (or switch to) Preview application. Preview has several graphical editing capabilities – including annotating, cropping, and rotating.
3. File Menu => New from Clipboard
4. File Menu => Save As
5. Save image in PNG format for Forum posting or use JPG format for Wiki pages
6. Remember where file saved (along with name) – forum editor has paper clip for attaching file. Wiki page has Upload Image Both have “choose file” to specify saved file.

Windows

1. Find the “PrintScreen” key on your keyboard (the key may be labelled PrtSc/PrntScr). Press Alt + PrtSc to put a copy of the active window in the clipboard buffer.
2. Then open Microsoft Paint, or some other graphics editor.
3. In the menu click EDIT>PASTE to paste the contents of the clipboard to your new graphic.
4. Choose FILE>>SAVE AS
5. Save the file with a meaningful name as a JPG, GIF or PNG file (not BMP/Bitmap as they are too large).
6. Remember where you save the file.

Snipping Tool

   Windows 7/8, Vista, and Experience Pack for Windows XP Tablet include a program called Snipping tool. Loading it automatically gives you a “cross hairs” so you can select the area of your screen to grab along with basic editing ability.

Jing

  Many forum users are using Jing (http://www.jingproject.com/) to make the captures. The free version will do both image and video captures of specific areas of your screen. You can then do minor edits if necessary. You can then upload to the free webspace they provide or save the capture locally on your computer.

Snagit

  The same company makes a paid program called Snagit.
  http://www.techsmith.com/screen-capture.asp

Camtasia

  http://www.techsmith.com/camtasia.asp

FastStone Capture

  http://www.faststone.org/FSCaptureDetail.htm

Greenshot

  Free and opensource, with a surprising number of features. (Though it could use a few more)
  http://sourceforge.net/projects/greenshot/

IrfanView

  A well known image viewer for quite some time.
  http://www.irfanview.com/

Gadwin

  They have both a free and a paid version – the free version works well.
  http://www.gadwin.com/printscreen/

Paint.NET

  Originally intended as a free replacement for the Microsoft Paint software that comes with Windows, it has grown into a powerful yet simple image and photo editor tool.
  http://www.getpaint.net/

PicPick

  Free for personal and non-profit use. You can edit, draw boxes, circles, etc., before saving. Easy to use.
  http://www.picpick.org/download

GIMP

  GIMP is an acronym for GNU Image Manipulation Program. It is a freely distributed program for such tasks as photo retouching, image composition and image authoring.

  GIMP is expandable and extensible. It is designed to be augmented with plug-ins and extensions to do just about anything, including advanced scripting.

  http://www.gimp.org/