Adding Image to Sheet from Drive

I would like to create a signature png file save in G Drive and have it paste into a cell with a menu item. I have set the image as public and an trying to use the shared URL, but this doesn't work adding =IMAGE or doing this programmatically. I have tried various pieces of code from the interwebs and have not been successful to date. Last attempt at code listed.

function mysig() {
  var ss = SpreadsheetApp.getActiveSpreadsheet();
  var sheet = ss.getActiveSheet();
  var rng = sheet.getRange(34,6);
  var url = "https://drive.google.com/file/d/id/view?usp=sharing"
  var fetch_img = UrlFetchApp.fetch(url);
  var blob = fetch_img.getBlob();
  Logger.log(fetch_img.getBlob())
  sheet.insertImage(blob, 6, 34);

}