![Mac Mac](http://www.effectmatrix.com/mac-appstore/PixelStyle_img/affinity-photo.jpg)
Is widely recognised as a quality free alternative to Photoshop in many regards.but it's not considered to be particularly successful in it's approach to embracing Mac OS X application design;) If you want something that isn't necessarily free but is at least inexpensive, then there are a number of other programs including and available in the Mac App Store. You could always try the cut down. For a good roundup, see this wonderful blog post from the Ask Different Community Blog for more info. Okay, mark me down for ignoring the 'free' part of the question, but I'm really quite fond of for the combination of editing and organizing that it does. It fills about 95% of what I used to use Photoshop for, plus I can keyword photos, maintain versions of edits, label faces and search for similar ones, and much more.
It's become the centre of my photo organizing and editing activities. Together with Apple Pages, I can do just about anything I want to do regarding photo editing, organization, and end use.
Here we provided many free Photoshop alternatives for Windows and MAC users which are quite powerful as Photoshop and offers the same tools as Gimp supports all major operating systems including Windows, Mac OS, Linux, Unix, BSD, etc. It supports most of the file formats including RAW.
It won't do 'flaming text' or other 'graphic arts' sorts of things that Photoshop does, though. I don't miss that.