how to move(to directory) base64 decoded image in laravel?

I have form, where i upload image in base64ecode

<input type=hidden value=.....(base64encode string) />

in laravel's method( where i handle input data) i have

$data = Request::all(); // get all input data
$img = base64_decode($data["img"]); // my decoded image

how can i move this decoded image in (any) directory? in laravels manual i've read about

$request->file('photo')->move($destinationPath);

but i dont know how to use it in my case

via Chebli Mohamed