title: Unknown argument on a function on github
body: <p>I found a good function on github for uploading images using php, but I do not know one of its arguments.</p>
  
  <pre><code>upload_image($_FILES,'file',250,'city',500,'../../uploaded/',1048576);
  </code></pre>
  
  <p><a href="https://github.com/MohammadKermani/php-image-upload" rel="nofollow noreferrer">Function on Github</a> </p>
  
  <ol>
  <li>What is 'file' in this function?</li>
  <li>Is this a trusted function to use in my website?</li>
  </ol>