$pager = array(
'https://pictures.site.com/12321412421.jpg',
'https://pictures.site.com/vsdvxzvbcx.jpg',
'https://pictures.site.com/fbf547457.jpg',
'https://pictures.site.com/assfdsf76.jpg'
)
$multi = curl_multi_init();
$channels = array();

foreach ($pager as $url) {
    $ch = curl_init();
    $ua = 'Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US) AppleWebKit/525.13 (KHTML, like Gecko) Chrome/0.A.B.C Safari/525.13';
    $destination = fopen(dirname(__FILE__).'/'.hash('sha256',rand()).'.jpg',"w+");
    curl_setopt($ch, CURLOPT_HEADER, true);
    curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
    curl_setopt($ch, CURLOPT_USERAGENT, $ua);
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_REFERER, $url);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_COOKIEFILE, dirname(__FILE__).'/cookies.txt');
    curl_setopt($ch, CURLOPT_FILE, $destination);
    curl_multi_add_handle($multi, $ch);
    $channels[$url] = $ch;
}
$active = null;
do {
    $mrc = curl_multi_exec($multi, $active);
} while ($active > 0);

while ($active && $mrc == CURLM_OK) {
    if (curl_multi_select($multi) == -1) {
        continue;
    }

    do {
        $mrc = curl_multi_exec($multi, $active);
    } while ($active > 0);
}

foreach ($channels as $channel) {
    curl_multi_remove_handle($multi, $channel);
}

curl_multi_close($multi);