regular expression all urls but those containing images ...

[hax]

since my head is about to explode maybe someone can help me:

I want to look for all urls except those that end with (.jpg|.gif|.png)


$prefix = '(http|https|ftp|telnet|news|gopher|file|wais)://';
$pureUrl = '([[:alnum:]/\n+-=%&:_.~?]+[#[:alnum:]+]*)';
$mygmsg = eregi_replace($prefix . $pureUrl, '<a
href="\\1://\\2" target="_blank"
class="normal">\\1://\\2</a>', $mygmsg);

here's what I'm doing no, but I want to replace images with something different ..