title: How to create an image file from a dataURL?
body: <p>I am trying to upload pictures to Parse.com, I do not have the files, but the dataURL's (because I resized the images), but need an image file to upload.</p>
  
  <p>Any tip is welcome.</p>
  
  <p>Here is the code for further details:</p>
  
  <pre><code>// First want to resize the image, where the result is a dataURL
  var dataURL;
  function resizePicture(file) {    // This file is the original image
      var reader = new FileReader();
      reader.onloadend = function() {
          var tempImg = new Image();
          tempImg.src = reader.result;
          tempImg.onload = function() {
              var MAX_WIDTH = 100;
              var MAX_HEIGHT = 150;
              var tempW = tempImg.width;
              var tempH = tempImg.height;
              if (tempW &gt; tempH) {
                  if (tempW &gt; MAX_WIDTH) {
                      tempH *= MAX_WIDTH / tempW;
                      tempW = MAX_WIDTH;
                  }
              } else {
                  if (tempH &gt; MAX_HEIGHT) {
                      tempW *= MAX_HEIGHT / tempH;
                      tempH = MAX_HEIGHT;
                  }
              }
              var canvas = document.createElement('canvas');
              canvas.width = tempW;
              canvas.height = tempH;
              var ctx = canvas.getContext("2d");
              ctx.drawImage(this, 0, 0, tempW, tempH);
              dataURL = canvas.toDataURL("image/jpeg"); // How can I convert this dataURL to an image file?
          }
      }
      reader.readAsDataURL(file);
  }
  
  // Then,  want to upload the image to Parse.com. 
  function savePicture() {
      var name = "productPicture.jpg";
      var parseFile = new Parse.File(name, dataURL); // Here instead of dataURL, I need an image file.
      parseFile.save().then(function() {
              // successful save
          }, function(error) {
              alert("The file either could not be read, or could not be saved to Parse.");
      });
  }
  </code></pre>