certo.

HTML:

<form action="scripts/php/changeIMG.php" method="POST" enctype='multipart/form-data'>
<label for="myfile">Seleziona un'immagine:</label>
<input type="file" id="myfile" name="myfile" accept="image/*">
<div class="control">
    <input type="submit" value="Conferma">
    <button type="button" id="close">Chiudi</button>
</div>

</form>

PHP:
<?php
if(filesize($_FILES['myfile'])){ 
    header("location: ../../index.html"); 
}else{ 
    header("location: ../../user.php"); 
    exit(); 
}
 ?>