title: Parse image size from JPEG
body: <p>I was wondering if there was an inexpensive way to get the width and height of a JPEG after loading an array of bytes.</p>
  
  <p>I know <code>JpegBitmapDecoder</code> can get the JPEG's pixel width and height but it loads alot of information as well, which I assume would be an expensive operation.</p>
  
  <p>Is there another way to get the width and height from the array of bytes without decoding it?</p>
  
  <p>Thanks</p>