PHP show image if post result equals

I have a form that posts to a page. I want to display an image if the value of the item posted equals "paypal".

I need to write something that says;

if $_POST['method'] equals "paypal" then show paypal.gif

if $_POST['method'] equals "mastercard" then show mastercard.gif

I hope I made a bit of sense, new to php trying to learn the best I can

If the methods have the same values as the file names, you can use this:

<img src="<?=$_POST['method']?>.gif" />