code: function determineWidthAndHeight(w, h, info) {
      if (!w && !h) {
        w = -96;
        h = -96;
      }
  
      if (w < 0) {
        w = -1 * info['w'] * 72 / w / this.internal.scaleFactor;
      }
  
      if (h < 0) {
        h = -1 * info['h'] * 72 / h / this.internal.scaleFactor;
      }
  
      if (w === 0) {
        w = h * info['w'] / info['h'];
      }
  
      if (h === 0) {
        h = w * info['h'] / info['w'];
      }
  
      return [w, h];
    }
docs: Image functionality ported from pdf.js