static S uploadToImageServer_rawBytes(byte[] imgData, S name) {
  S page = postPage(imageServerURL() + "upload", "data", bytesToHex(imgData), "name", name);
  print(page);
  Matcher m = Pattern.compile("/raw/([0-9]+)").matcher(page);
  if (!m.find()) null;
  ret snippetImgLink(m.group(1));
}