//в  $uploadfile  /images/.... . jpg
    move_uploaded_file($filesdata['tmp_name'], $uploadfile);
                $image = new Imagick();
                $image->readImage($uploadfile);

                $watermarck =  new Imagick();
                $watermarck->readImage('images/water.png');

                 $image->compositeImage( $watermarck, imagick::COMPOSITE_OVER, 0, 0);

                file_put_contents ($uploadfile,$image);

<?php
$im = new Imagick ();
$im->newImage (300, 225, "blue");
$im->writeImage ("test_0.jpg"); // fails with no error message