Replace all image sources that are local with PHP
<p>I need to replace all of the image sources on my website from <code>&lt;img src="images/etc.png" /&gt;</code> to have <code>bloginfo('template_url')</code> in front of them.</p>

<p>I know I can do this manually but just for convenience I would like PHP to do this itself. I know it can be done, I tried with str_replace but I just can't figure it out. I'm not a PHP whiz!</p>

<p>Thanks to anyone who can help.</p>
