Image Editing Toolset for Mac

All of the following are free and available on the Mac:

• Grab - Awesome tool for taking snapshots of on screen material.
• iPhoto - Decent~ish for cropping.
• Preview - Pretty good for cropping. You can follow the instructions given here. Hint: Select what should remain then press "cmd+k" to crop out the rest.
• Gimp
  • Great for smudging out unwanted portions of existing images.
  • Converting regular icons into those that look disabled

Inkscape - Some discoveries are only made on mac

For those who leave the comfortable realm of Windows behind and enter the rather strange and initially maddening world of the Mac, the only thing that can possibly hit harder than not being able to use the keys and shortcuts like before, has to be the glaring lack of some MSPaint like utility.

Well, you may quickly find solace by going out and downloading either Gimp or Inkscape.

My personal vote would lean heavily towards Inkspace because of the abundance of excellent resources and tutorials when it comes to getting started with this tool:

1. inkscape-class-day-1
2. inkscape-class-day-2
3. inkscape-class-day-3
4. inkscape-class-day-4

A lot of screencasts are available as well.

Afterwards to get your creativity flowing use the following two awesome tutorials to create some mac/iPhone icons of your own:

• http://cocoawithlove.com/2009/11/creating-iphone-and-mac-icons-using.html
• http://cocoawithlove.com/2009/11/creating-iphone-and-mac-icons-using_06.html