Image_style_url with [default_image] I am trying to print a commentator's avatar picture in the comments.tpl.php

&lt;img src="
        &lt;?php
            if ($picture) {
                print image_style_url('comment_picture', $comment-&gt;picture-&gt;uri);
                ?&gt;"&lt;/img&gt;


which works as desired. However it doesn't post the default_picture if the user does not have a profile picture uploaded.

I've tried using [default_image] but then nothing happens

&lt;img src="
        &lt;?php
            if ($picture) {
                print image_style_url('comment_picture', $comment-&gt;picture-&gt;uri);
             } else {
                print image_style_url('comment_picture', [default_image]);
            }
                ?&gt;"&lt;/img&gt;
Use below code in else condition...

$user = user_load($comment-&gt;uid);
print theme('user_picture', array('account' =&gt; $user));


OR

$filepath = variable_get('user_picture_default', '');
$default_image = theme('image_style', array('style_name' =&gt; $style, 'path' =&gt; $filepath, 'alt' =&gt; '', 'title' =&gt; ''));
print $default_image;