This will fill a circle on this Image.

.fillCircle( x, y, diameter, isCentred = false )

Draws a filled circle, at the location given.

'diameter' is used for both the width and height of the circle.

.fillCircle( x, y, diameter, xAlign, yAlign )

The same 'fillCircle' method, but with x and y alignment options. See the article on How Alignment Works for details.