nohup php File_Check.php &

├── File_Check.php
├── upload
└── data

<?php
while(true){
    if($result = is_scandir("./upload")){
        foreach($result as $key=>$value){
            rename("./upload/$value","./data/$value");
        }
    }
    sleep(3);
}

function is_scandir(string $dirname="",array $ext_list = ["png","jpg"]){
    $is_filelest = [];
    $result = scandir($dirname);
    foreach($result as $key=>$value){
        $ext = substr($value, strrpos($value, '.') + 1);
        if(in_array($ext,$ext_list,false)!== false){
            $is_filelest[] = $value;
        }
    }
    return count($is_filelest)>0 ? $is_filelest : false;
}