heightCharts改变图表内图标的样式：链接外部图片

series: [{

            name: '东京',

            marker: {

                 symbol: 'url(https://www.highcharts.com/demo/gfx/sun.png)'     //链接外部图片

            },

            data: [7.0, 6.9, 9.5, 14.5, 18.2, 21.5, 25.2, {

                y: 26.5,

                marker: {

                    symbol: 'url(https://www.highcharts.com/demo/gfx/sun.png)'    //链接外部图片

                }

            }, 23.3, 18.3, 13.9, 9.6]

        }, {

            name: '伦敦',

            marker: {

                symbol: 'diamond'

            },

            data: [{

                y: 3.9,

                marker: {

                    symbol: 'url(https://www.highcharts.com/demo/gfx/snow.png)'

                }

            }, 4.2, 5.7, 8.5, 11.9, 15.2, 17.0, 16.6, 14.2, 10.3, 6.6, 4.8]

        }]