HD wallpaper: E-mc2 written on chalkboard, woman writing mathematical equations on blackboard using chalk online crop
- Double click dark area to toggle "Crop" and "Drag" mode
- Keep aspect ratio: hold Shift key when resizing the crop box
- Crop a square image: hold Shift key when cropping on the image
- Scroll mousewheel to zoom in & zoom out wallpaper
- Press Esc key to reset current crop box