Pixelmator is a beautifully designed, easy-to-use, fast and powerful image editor for Mac OS X has everything you need to create, edit and enhance your images.
Pixelmator is a layer-based image editor. You can quickly create layers from your photos, other pictures, from selections or even your iSight. Yes, Pixelmator can add a layer to your composition directly from your Mac’s little camera. Not only can you link and arrange added layers, but Pixelmator allows you to blend layers, change their opacity, create clipping masks or even add layer masks to hide some portions of layer.
It even has iSight compatibility so you can have it take a picture and add it as a layer for editing.
More info here.
MacDailyNews Take: We use Pixelmator daily and recommend it highly.