Resizing a image.

[Asterik]

Slowly going insane over this.

This is my resize function:

function imageresize($img, $thumb, $thumb_width, $thumb_height)
{
	$ext=explode('.',$img);			// Isolere exstension
	$ext=strtolower($ext[count($ext)-1]);		// Gjere CAPS til lower.
	echo "$ext";
	if($ext == jpg)
	{
		$src_img = imagecreatefromjpeg("$img"); 
		$dst_img = imagecreatetruecolor($thumb_width,$thumb_height); 
		imagecopyresampled($dst_img, $src_img, 0, 0, 0, 0, $thumb_width, $thumb_height, 0, 0); 
		imagejpeg($dst_img, "$thumb", 15); 
		imagedestroy($src_img); 
		imagedestroy($dst_img); 
	}
}

This is the code i'm calling the function with:

copy($imagefile, "$uname/$imagefile_name"); 
imageresize("$uname/$imagefile_name", "$uname/thumbs/$imagefile_name", 25, 25);

No errors...just a completly black image, thus empty.
Why on earth is this happening? Can anyone spot an error in my code, cos' i sure can't at this hour.