Imagecached profile pictures not showing up for posts or comments

I'm using Imagecache with Imagecache profiles to generate the various sizes of image for use in profiles and views, but they don't seem to be showing up in nodes and comments (even though the settings in admin/user/settings are correct) using the standard picture code:

<?php
    print $picture;
  } ?>

Could someone tell me what the correct could should be if not this?

Thanks,

Alex