For PickLanguage.pm it's nice to have flags, which you'll find in the attached gimp-file.
Copy the needed flags to the name of the language "Nederlands.gif, Deutsch.gif, English.gif and put these in /extras.
Then change the (actual) PickLanguage like:
$outputLinks .=
'<span class="flags" style="margin:1px;background-color:#ffffff;">
<a href="?op=setLanguage;language='. $language .'"><img src="/extras/'. $linkText . '.gif" alt="'.$linkText.'" style="border:0px;" ></a>
</span>';