function upload(uri, filename, tag){
  filename = filename || get_filename()
  uri = (uri && ! uri.target) ? uri : lastGif
  tag = tag || "shader"

  var blob = dataUriToBlob(uri)
  uploadImage({
    blob: blob,
    filename: filename,
    username: user.username,
    tag: tag,
    success: function(data){

      // data.url
      // data.filesize
      // data.success

      console.log(data);
      $("#uploaded-url").show().focus().val(data.url)
      $("#uploaded-url + br").show()
      status && status("uploaded");
    },
    error: function(data){
      console.log(data)
      status("error uploading: " + data.error)
    }
  });
}

function save (){
  var filename = get_filename()
  var blob = dataUriToBlob(lastGif)
  saveAs(blob, filename);
}