is a free, open source pixel art editor for Mac OS X. With features like color palettes, layers, patterns, and Tile View, Pixen includes all the tools you need to create pixel art on your Mac. Pixen also makes creating animations fun and easy.
Features:
Animations
Create and arrange image frames in the filmstrip view to piece together animations; export animations as animated GIFs, QuickTime movies, or even spritesheets!
Tools
Leverage Pixen's wide array of tools when composing pixel art: Pencil, Eraser, Eyedropper, Zoom, Rectangular Selection, Magic Wand, Lasso, Move, Fill, Line, Rectangle, and Ellipse.
Layers
Take advantage of the flexibility layers provide when working with complex pixel art.
Color Palettes
Add and organize commonly-used colors into palettes.
Patterns
Define custom patterns to use while drawing with the pencil, line, or eraser tool (instead of a single pixel).
Backgrounds
Pick a flat, striped or checkered background (or even a custom image) to be drawn beneath the canvas.
Tile View
Preview and edit images as they are tiled across the window.
Grid + Alignment Crosshair
Let the grid and the alignment crosshair guide you in placing pixels just where you want them.
Preview
While editing at high zoom levels, use the Preview window to view the canvas scaled out.
Left and Right Tools
Assign a different tool to the left and right mouse button. For example: pencil on the left; eraser on the right.
Tablet Support
Pixen supports pressure-sensitive drawing tablets and maps pressure to color opacity.
Hotkeys
Customize tool hotkeys to ease the transition from other image editors.
Full Screen
Work with all your favorite tools in full screen mode on OS X Lion.
