Design a premium children's coloring game screenshot showing a beautiful butterfly illustration transitioning naturally from black-and-white line art into vibrant hand-painted colors as a marker colors across the page. The transformation should feel smooth and satisfying. The page sits on a clean wooden desk with a few colorful crayons placed around it. Use soft painterly illustration, thick outlines, and premium mobile game presentation. Add the headline "Magic Color Reveal" in a bright rounded banner.