title: UIMarkupTextPrintFormatter never renders base64 images
body: <p>Im creating a pdf file out of html content in swift 3.0:</p>
  
  <pre><code>/**
   *
   */
  func exportHtmlContentToPDF(HTMLContent: String, filePath: String) {
      // let webView = UIWebView(frame: CGRect(x: 0, y: 0, width: 694, height: 603));
  
      // webView.loadHTMLString(HTMLContent, baseURL: nil);
  
      let pdfPrinter = PDFPrinter();
      let printFormatter = UIMarkupTextPrintFormatter(markupText: HTMLContent);
      // let printFormatter = webView.viewPrintFormatter();
  
      pdfPrinter.addPrintFormatter(printFormatter, startingAtPageAt: 0);
  
      let pdfData = self.drawPDFUsingPrintPageRenderer(printPageRenderer: pdfPrinter);
  
      pdfData?.write(toFile: filePath, atomically: true);
  }
  
  /**
   *
   */
  func drawPDFUsingPrintPageRenderer(printPageRenderer: UIPrintPageRenderer) -&gt; NSData! {
      let data = NSMutableData();
  
      UIGraphicsBeginPDFContextToData(data, CGRect.zero, nil);
  
      printPageRenderer.prepare(forDrawingPages: NSMakeRange(0, printPageRenderer.numberOfPages));
  
      let bounds = UIGraphicsGetPDFContextBounds();
  
      for i in 0...(printPageRenderer.numberOfPages - 1) {
          UIGraphicsBeginPDFPage();
  
          printPageRenderer.drawPage(at: i, in: bounds);
      }
  
      UIGraphicsEndPDFContext();
  
      return data;
  }
  </code></pre>
  
  <p>Everything is rendered fine except my base64 encoded images. The HTML content itself in a webview or inside safari or chrome browser is presented correctly and is showing all images correctly. But the images are never rendered into the pdf.</p>
  
  <p>Why are the images not rendered and how can I get them to be rendered?</p>