title: filectime vs filemtime for file modification time?
body: <p>I'm trying to ensure some images aren't cached when they're modified but which would be more suitable for this <code>filectime</code> or <code>filemtime</code>?</p>
  
  <p>I can't really see much difference from the php manuals? Would either be faster?</p>
  
  <pre><code>&lt;img src="/images/123.png?&lt;?=md5(@filectime("/images/123.png"))?&gt;" /&gt;
  &lt;img src="/images/123.png?&lt;?=md5(@filemtime("/images/123.png"))?&gt;" /&gt;
  </code></pre>
  
  <p>Also is there a function like this that doesn't emit an <code>e_warning</code> on file error? </p>
  
  <p>Ideally I don't want to ever serve just the question mark <code>&lt;img src="/images/123.png?" /&gt;</code></p>