Manage colors and their thumbnails by clicking Products in the left hand sidebar and select Color Manager.
Sort, publish and unpublish colors directly in the listing page. To make further edits, click the color name.
Change the parent color, or change the color of the color swatch image.
You may change the color swatch by using the color code (hexadecimal), you may type in the code, or use a color picker. You can also upload an image to pick a color from.
Press Save when done.