I am trying to create new empty image with width and height and save it as png to file.

This is what i got:

```
var myImage = new Image(200, 200);
myImage.src = 'picture.png';

window.URL = window.webkitURL || window.URL;

var contentType = 'image/png';

var pngFile = new Blob([myImage], {type: contentType});

var a = document.createElement('a');
a.download = 'my.png';
a.href = window.URL.createObjectURL(pngFile);
a.textContent = 'Download PNG';

a.dataset.downloadurl = [contentType, a.download, a.href].join(':');

document.body.appendChild(a);

```

I am trying to get transparent image with given width and height in `var myImage new Image(200, 200)` as the output on the download.