title: How to save multiple UIImage to a file iPad
body: <p>I have a PDF reader that displays pages of the document. What I want to do is allow the user to draw over the PDF in a transparent view. Then I want to save the drawing (UIImage) to disk. If at all possible, I don't want to have the documents folder filled with files like documentName_page01.png, documentName_page02.png  for every page that is drawn over. </p>
  
  <p>However, I can't figure out how to store these UIImages into a single file without it becoming unwieldy and memory intensive.</p>
  
  <p>Any ideas appreciated.</p>