title: What's the meaning of `transparent` in CSS background property?
body: <p>What does this class say? What is transparent doing here in background?</p>
  
  <pre><code>background: url("../images/abc.jpg") repeat-x scroll 0 0 transparent;
  </code></pre>
  
  <p>Will the browser convert a jpg image into transparent? But aren't only pngs transparent?</p>