imageellipse() draws an ellipse centered at cx, cy (top left is 0, 0) in the image represented by image. W and h specifies the ellipse's width and height respectively. The color of the ellipse is specified by color.
Note: This function was added in PHP 4.0.6 and requires GD 2.0.2 or later which can be obtained at http://www.boutell.com/gd/
See also imagearc().