Screen capture and basic image editing using "Preview" on a Mac

Tech Tip

Screen Capture and Preview as Image Editor

◦    [Cmd + Shift-3] This will give you a cross-hairs, which allows you to drag a box around a region, and snap a picture of that, which will be saved as a picture file to your desktop.

◦   [Cmd + Shift + 4] This will snap a picture of everything showing on your screen, and save it as a picture file to your desktop.

◦   [Ctrl + commands above] If you press another modifier key [ctrl] while performing the keystrokes the snapshot will be saved to your clipboard. 
This lets you paste it into an e-mail or Word document without dragging the file in first.

◦   [Cmd-Shift-4] + [Spacebar] 
Using this key combination, you will be able to capture a certain stand-alone objects on your Mac, like the dock, the menubar, a whole window, etc. This is helpful for snapping pictures of entire objects to give context.

Once you have all these pictures, you may not know that you can use the “Preview” program to do basic image adjustments like cropping to make them more useful.

Cropping

You can double click one of your saved picture files to open it in Preview, then use the “select” tool to drag a box around the part of the image you want to keep, then click the “Tools” menu, then “Crop”.

Adjust Size/Brightness/Exposure/Contract/Rotate Images

The other items on the tools menu are helpful, too.  You can adjust the size of pictures, change the brightness, exposure, and contract, and rotate or flip images.