canvas

<canvas id="c" width="14" height="14"></canvas>
<br/>
<img id="img" src="bla.png"/>

<script>
var canvas = document.getElementById("c");

var ctx = canvas.getContext("2d");

var image = document.getElementById("img");

ctx.drawImage(image,0,0,14,14);

var imageData = ctx.getImageData(0,0,14,14);

var data = imageData.data;

var width = imageData.width;
var height = imageData.height;

var rgbArray = [];

for(var i=0;i<height*width*4;i=i+4){
	rgbArray.push({r: data[i], g: data[i+1], b: data[i+2], a: data[i+3]});
}

var coordinates2dArray = [];

for(var i=0;i<height;i++){
	
	coordinates2dArray[i] = [];
	
	for(var j=0;j<width;j++){
		coordinates2dArray[i].push(rgbArray[(i*width)+j]);
	}
}

console.log(coordinates2dArray);

for(var i=0;i<coordinates2dArray.length;i++){
	for(var j=0;j<coordinates2dArray[i].length;j++){
		
		var currentCoordinate = coordinates2dArray[i][j];
		
		if(!(currentCoordinate.r == 255 && currentCoordinate.g == 255 && currentCoordinate.b == 255 && currentCoordinate.a == 255)){
			console.log(i + " " + j);
		}
	
	}

}


</script>