Description:
------------
I often prefer to use for input elements namestrings in array notation, similar to 

echo '<input type="image" src="/img/lupe.gif" name="btn[show][' . $id . ']">';

This is very handy, unfortunately it doesn't work when Input-Type = Image.

Result will be:
Array
(
    [btn] => Array
        (
            [show] => Array
                (
                    [3] => 9
                )

        )
)

Looking into the http-transfer, everything is still ok:

 Content-Disposition: form-data; name="btn[show][1].x"
 Content-Disposition: form-data; name="btn[show][1].y"

Due to the "point substitution" in combination with the array spelling, the x-coordinate will be replaced by the y-coordinate



Expected result:
----------------
I would be glad, if for further PHP-Versions the result could be:

(
    [btn] => Array
        (
            [show] => Array
                (
                    [3] => Array
                      {
                          [x] => 9
                          [y] => 27
                      } 
                )
        )
)

For compatibility reasons, the translation for simple names perhaps should remain the same
 
  <input type="image" name="image" ... >

becomes furthermore to

   $_POST['image_x'] = 9
   $_POST['image_y'] = 27