[Solved]-Highcharts: How to set unique images on top of bar chart serie-Highcharts

In the first case, you should disable grouping on series:

plotOptions: {
    series: {
        grouping: false
    }
}

Live demo: http://jsfiddle.net/BlackLabel/v7qx1s5u/

In the second case, you can define individual data label for point:

series: [{
    type: 'column',
    data: [{
            x: 0,
            y: 1,
            dataLabels: {
                align: 'center',
                enabled: true,
                useHTML: true,
                formatter: function() {
                    return '<img src="https://www.highcharts.com/samples/graphics/sun.png"><img>';
                }
            }
        },
        [1, 2],
        [2, 3]
    ]
}]

or in formatter function define some rules where the data label should be some image:

    dataLabels: {
        align: 'center',
        enabled: true,
        useHTML: true,
        formatter: function(){
            if (this.point.index === 1){
                return '<img src="https://www.highcharts.com/samples/graphics/sun.png"><img>&nbsp;';
            }

        }
    }

Live demo: http://jsfiddle.net/BlackLabel/72Lahvp4/