Drag and drop images, and not links, between windo

I'm trying to make a drag and drop uploader in HTML5 with the added requirement of being able to do so with files dragged from other websites I don't own and can't edit (mostly images).

In this case, on the ondrop event, instead of downloading the image from the local computer using e.dataTransfer.files and posting it, I retrieve the URL with e.dataTransfer.getData('URL') and post it to the server for it to download server-side.

Works fines, except when I drag an image enclosed in a link.

It works when initiating drag from an <img> element, but not with an <img> enclosed in <a> element. In the latter one, e.dataTransfer.getData('URL') gives me the href of the link, not the src of the image.

I looked into e.dataTransfer.getData() to see if it accepted other arguments that could help. The other alternative was "Text", and it brought up the same results as "URL".

Is there a way to get the image URL or am I doomed because the browser doesn't actualy carry the image URL when dragging an image enclosed in a link (ie : I'm dragging the link, not the image)?

UPDATE

To illustrate I created a jsfiddle here : https://jsfiddle.net/2m58rfou/
And another one with 2 images to demonstrate my problem here : https://jsfiddle.net/870asboa/
Open them in separate tabs and try dragging both images in the drop zone.

With the first image, I get what I want : https://www.gstatic.com/webp/gallery/1.sm.jpg
With the second one I get http://www.google.com/, the link the image is enclosed in, rather than the image address.

In the second scenario, is there a way to get the image address and not the link in the ondrop listenner, or is it impossible ? (remember that the images can be on any website, I can't catch any dragstart event, basically only the drop one).

At dragover event handler, iterating event.dataTransfer.types

The DataTransfer.types read-only property is an array of the drag data formats (as strings) that were set in the dragstart event. The order of the formats is the same order as the data included in the drag operation.

the array contains three types:

text/plain
text/uri-list
text/html

text/html is the html string of the dragged <img> element.

Get the string using by passing "text/html" to .getData(), then either extract src of html string using RegExp or create an element and append the html string to the element, then get src of <img> element using .src.

holder.ondrop = function (e) {
  e.preventDefault();       
  this.className = '';
  var img = e.dataTransfer.getData("text/html");
  var div = document.createElement("div");
  div.innerHTML = img;
  var src = div.firstChild.src;
  console.log(div.firstChild, src);
  results.innerText = src;
}

jsfiddle https://jsfiddle.net/2m58rfou/6/