title: File rename regex adding unwanted suffix
body: <p>I have a problem with <code>rename -v 's/\.jpg$/\_120x120.jpg/' *.jpg</code></p>
  
  <p><code>zzr31_120x120.jpg</code> renamed as <code>zzr31_120x120_120x120.jpg</code></p>
  
  <p>How can I make it more clear that it would rename only those that don't have 120х120?
  And on top of that to make it not only <code>jpg</code> but for <code>gif</code> and <code>png</code> in one command if possible?</p>