This one is usefull for IE10+: http://msdn.microsoft.com/en-us/library/hh779016(v=vs.85).aspx
something like:
<!DOCTYPE html>
<html>
<head>
<title>title</title>
</head>
<body>
<img id="img1" src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAADIAAAAyCAYAAAAeP4ixAAAASUlEQVRo3u3PAQ0AIAwDsIGC+TcL
LkhOWgddSU6Ga5udT4iIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIi8cQEjUgGT
mE6z3QAAAABJRU5ErkJggg==" />
<canvas id="canvas1"></canvas>
<script>
var image = document.getElementById('img1');
var canvas = document.getElementById('canvas1');
var ctx = canvas.getContext('2d');
ctx.drawImage(image, 0, 0, image.width, image.height);
window.navigator.msSaveBlob(canvas.msToBlob(), 'drawingFileName.png');
</script>
</body>
</html>