<?php


    $foo = '{"images":{"standard_resolution":{"url":"http:\/\/scontent-a.cdninstagram.com\/hphotos-xfa1\/t51.2885-15\/10593467_370803786404217_1595289732_n.jpg","width":640,"height":640}}}';
    $bar = json_decode($foo, true);

    $baz = 
    parse_url($bar['images']['standard_resolution']['url'], PHP_URL_HOST) . 
    parse_url($bar['images']['standard_resolution']['url'], PHP_URL_PATH);

    echo $baz;