https://rt.cpan.org/Ticket/Display.html?id=9798
Also, it wasn't testing pnm (pnm vs ppm mix-up)
+ - update the documentation of hardinvert to match the change in 0.62.
+ https://rt.cpan.org/Ticket/Display.html?id=59785
+
Imager 0.75 - 20 Jun 2010
===========
=item C<hardinvert>
-inverts the image, black to white, white to black. All channels are
-inverted, including the alpha channel if any.
+inverts the image, black to white, white to black. All color channels
+are inverted, excluding the alpha channel if any.
$img->filter(type=>"hardinvert")
or die $img->errstr;