From Pixelmator Team:
Pixelmator is an image editor for Mac OS X that allows you to create, edit, and enhance your images. Interface designed for work with images, layers-based image editing, use over 20 tools for selecting, crop, painting, retouching, typing, measuring, and navigation. Use over 15 color correction tools, use over 50 filters, adjust image size and resolution. Transform images, layers or selections using transform tools, fill and stroke images, layers or selections, photo browser offers quick access to iPhoto Library, events, albums, smart albums, and pictures folder. Use your iSight camera to add pictures to your compositions. Includes automator actions for converting, resizing, enhancing, adding special effects, and transforming images. Image processing is powered by core image and open GL.