title: php : How to create a string of image binary without saving it to a file?
body: <p>I have an image variable,</p>
  
  <pre><code>$im = imagecreatetruecolor(400, 300);
  </code></pre>
  
  <p>Is there anyway to get a string of binary of this image in jpeg format without saving it to a file?
  Thanks!</p>