It also shows how to use external graphic files for point features and how to set their size: If either graphicWidth or graphicHeight is set, the aspect ratio of the image will be respected. If both graphicWidth and graphicHeight are set, it will be ignored. Alternatively, if graphicWidth and graphicHeight are omitted, pointRadius will be used to set the size of the image, which will then be twice the value of pointRadius with the original aspect ratio.