<?php
$dir = scandir('C:\Users\Administrator\Desktop\images');
echo '<pre>';
// print_r($dir);
$gif = array();
$png = array();
$jpg = array();
foreach ($dir as $key => $value) {
    $sub = strrchr($value,'.'); 
    if ($sub == '.jpg') {
        array_push($jpg, $value);
        //存入到jpg數組裡
    }
    if ($sub == '.png') {
        //存入到png數組裡
        array_push($png, $value);
    }
    if ($sub == '.gif') {
        //存入到gif數組裡
        array_push($gif, $value);
    }
}
print_r($gif);
print_r($png);
print_r($jpg);