PikoPixel is a free, open-source application for drawing and editing pixel-art images and icons.

Features:

• Easy to use
• Unlimited undo
• Supports multiple layers
• Customizable canvas background and grid patterns
• Hotkey-activated popup panels
• Export upscaled images
• Supports linear (gamma-correct) color blending

Originally a Mac app, PikoPixel runs natively on GNU/Linux by using the GNUstep framework.