PencilSheep is a free professional image editor with full GPU acceleration, interactive filter layers, and HDR support. PencilSheep provides all the features you'd expect to find in a professional image editor, such as layers, filters, layer styles, adjustment layers, masks, selections, undo/redo, and various different tools. In addition to that, PencilSheep adds many new features, such as interactive filter layers, full HDR support, and full GPU acceleration. PencilSheep executes all performance-critical operations (blending, filters, paint tools, etc.) on the GPU. Unlike traditional image editors (which either don't use GPU computing at all, or only offer partial GPU acceleration), PencilSheep has been specifically designed from the ground up to fully utilize the GPU for all image manipulations. For many tasks, PencilSheep is orders of magnitude faster than traditional image editors.