@nehasingh

For dynamic data, updating the position of image after adding new dataPoint has to be handled. Please take a look at below code snippet for the same.

var updateChart = function () {
  yVal = yVal + Math.round(5 + Math.random() * (-5 - 5));
  dps.push({ x: xVal,y: yVal });
  xVal++;
  if (dps.length > 10)
  {
    dps.shift();
  }
  chart.render();
  addMarkerImage(chart);
};

function addMarkerImage(chart) {
  var data = chart.options.data[0];
  for(var i = 0; i < data.dataPoints.length; i++) {
    customMarkers.push($("<img>").attr("src", data.markerImageUrl)
                       .css("display", "none")
                       .css("height", 20)
                       .css("width", 20)
                       .appendTo($("#chartContainer>.canvasjs-chart-container"))
                      );   
    positionMarkerImage(customMarkers[i], i);
  }            
}

function positionMarkerImage(customMarker, index){ 
  var pixelX = chart.axisX[0].convertValueToPixel(chart.options.data[0].dataPoints[index].x);
  var pixelY = chart.axisY[0].convertValueToPixel(chart.options.data[0].dataPoints[index].y);

  customMarker.css({"position": "absolute", 
                    "display": "block",
                    "top": pixelY - customMarker.height()/2,
                    "left": pixelX - customMarker.width()/2
                   });
}

var updateId = setInterval(function () { updateChart();}, updateInterval);

Please refer to this JSFiddle for complete code.

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