<?php
if(!isset($_GET['a'])) $_GET['a']='';
switch($_GET['a']){
    case '':
?>
    <form action="?a=upload" method="post" enctype="multipart/form-data">
        Poza: <input type="file" name="img" />
        <input type="submit" value="upload" />
    </form>
<?php
    break;
    case 'upload':
        $nume='micku7zu';
        $w=$h=100;
        $poza=$_FILES['img'];
        if(($error=upload($poza, "poze/".$nume, $w, $h))=='')
            echo 'este ok';
        else
            echo $error;
    break;
}

/* function for upload */
/* upload($_FILES["input_name"], "where_to_put/the_photo", 100, 100); */

function upload($file, $name, $w=100, $h=100){
    $error='';

    $oldname=$file["name"];
    $uploadedfile=$file["tmp_name"];

    $x=explode(".", $oldname);
    $extension=strtolower($x[count($x)-1]);

    switch($extension){
        case 'jpg': case'jpeg': $src = imagecreatefromjpeg($uploadedfile); break;
        case 'png': $src = imagecreatefrompng($uploadedfile); break;
        case 'gif': $src = imagecreatefromgif($uploadedfile); break;
        default: $error='Poza trebuie sa fie JPG, PNG sau GIF!'; break;
    }

    if($error==''){
        list($width,$height)=getimagesize($uploadedfile);

        $tmp=imagecreatetruecolor($w, $h);
        imagecopyresampled($tmp, $src, 0, 0, 0, 0, $w, $h, $width, $height);

        imagejpeg($tmp,$name.".jpg",100);

        imagedestroy($src);
        imagedestroy($tmp);
    }

    return $error;
}
?>