This seems simple, but I tried: convert -size 100x100 xc:none -fill red -draw 'circle 50,50 0,50' red-circle.png convert -size 100x100 xc:none -fill red -draw 'circle 50,50 0,49' red-circle.png And numerous other variations, it either pushes one side too much or seems to be one pixel too small. -- Bob