title: Mutagen : how to extract album art properties?
body: <p>I am trying to get properties (just width &amp; heigth so far, but probably more later) of an album art picture from an mp3 file using python 3.7.1 and mutagen 1.42, but nothing seems to work so far. I am yet able to extract some other information correctly</p>
  
  <p>The doc is telling about <a href="https://mutagen.readthedocs.io/en/latest/api/id3_frames.html#mutagen.id3.APIC" rel="nofollow noreferrer">APIC</a>, but trying to display all tags doesn't show anything related to any picture (and my mp3 test files <em>does</em> have album pictures) :</p>
  
  <pre><code>import os,sys
  from mutagen.mp3 import MP3
  from mutagen.easyid3 import EasyID3
  
  song_path = os.path.join(sys.argv[1]) # With sys.argv[1] the path to a mp3 file containing a picture
  track = MP3(song_path, ID3=EasyID3)
  pprint(track.get('title')[0] + ' ' + str(track.info.length) + 's, ' + str(int(track.info.bitrate / 1000)) + 'kbps')
  print(track.keys())
  </code></pre>
  
  <p>The result, using a file of mine :</p>
  
  <pre><code>&gt; Exponential Tears 208.0s, 205kbps
  &gt; ['album', 'copyright', 'encodedby', 'length', 'title', 'artist', 'albumartist', 'tracknumber', 'genre', 'date', 'originaldate']
  </code></pre>
  
  <p>(This mp3 file does have an embedded picture, that I can see with any music software I use.)</p>
  
  <p>I have found a lot of different ways of handling this with mutagen, but some seems outdated, others just doesn't work, I don't understand what I am missing here.</p>
  
  <p>Any help here would be gladly appreciated</p>