How to draw
Pick a color from the palette and click or drag on the grid to paint squares. Choose Eraser to clear squares and Fill to flood an area of one color with another. Undo steps back through your last 50 changes. The grid can be 8 × 8 up to 32 × 32 squares; changing the size keeps the top-left part of your picture.
Press Download PNG to save the picture. Choose how big each pixel is in the file: a pixel size of 16 turns a 16 × 16 drawing into a crisp 256 × 256 image. Empty squares stay transparent, so you can put the sprite on any background. Your work is saved in this browser and is there when you come back.
Ideas
Small grids force simple shapes: try an emoji, a heart, a character icon, a tiny landscape, a game sprite or a profile picture. Work from the outline in a dark color, then fill the areas, then add highlights. Drawing on a phone works too: touch and drag.
Is my picture uploaded? No. Can I use the PNG commercially? The picture is yours. To find a color's code, see the Color Picker.