modifying a filename extension on a php code

modifying a filename extension on a php code

sorry because I don't know how to ask the question
I have here a code in php
$productDetails['country'][0]['image']
which output is:
http://localhost/wine-works.co.uk-tester/wp-content/uploads/2013/09/canada-wine_shop.jpg
how do I change the filename to look like this:
http://localhost/wine-works.co.uk-tester/wp-content/uploads/2013/09/canada-wine_shop-25x17.jpg