some help

[AN-net]

ok im using a php file as way to have an image displayed. i want it to like <img src="http://www.blah.com/blah.php?do=image&id=666">
but it doesnt work. it only works if its just blah.php and nothing after it, is there anyway around this or fix?

heres my code:

PHP Code:

if($do=="image"){
if(empty($a)){
header("Location: $vboptions[bburl]/images/error.gif");
}
else{
header("Location: $settings[imagelink]");
}
}