http://webintents.org/save image/* service

gistfile1.js

window.addEventListener("load", function() {
  if(window.intent && window.intent.action === "http://webintents.org/save") {
    var data = window.intent.data;
    
    if(data instanceof Blob) {
      // do something with the blob.

    }
    else {
      // do something with the object.
    }
  }
}, false);