Steam API PHP JSON超时？

I got this to work on a smaller Steam group, but I'm trying to run it on a larger steamgroup and it eventually gives me a 504 timeout error. Am I missing something? Or would this be a server fix I would need to do?

<?php 

 $group = simplexml_load_file('http://steamcommunity.com/groups/revgame/memberslistxml?xml=1');

    foreach ($group->members as $groupinfo) {
        $members = $groupinfo->steamID64;
    }

    foreach ($members as $m) {
        $memberinfo[] = json_decode(file_get_contents('http://api.steampowered.com/ISteamUser/GetPlayerSummaries/v0002/?key=APIKEY&steamids=' . $m),true);
        $avatar = $mi['response']['players']['0']['avatar'];
        echo '<img src="'.$avatar.'" />';

            }

    ?>