what did you mean with:
Help me find a script that plugin Gallery.
did you mean something like: simple lightbox?
if yes look at my post inside this thread to get a sample that should work.
primary you need :
if ( function_exists('slb_activate') ){
$content = slb_activate($content);
}
where $content is output of gallery before you echo it echo.
but you could add any js that provide the popup-functionality when you know how to structure your output and how to apply the needed js.
