Transparent Watermark: Apply a transparent watermark to protect images

transparentWatermark class
v 1.01

This classe inserts watermark in image with transparent and randomize effects.
It protects image rights and avoid watermark clearing with softwares.

Constructor may have one parameter : name of stamp image. This file must
be a JPEG or PNG image.

setStamp( filename) method is used to set or change stamp image.

markImageFile ( image1, image2) method is used to apply stamp on image1. 
If image2 is set, result is saved in image2, else result is printed to stdout with mime-type.

markImage ( imageResource) method is used to apply stamp on image resource
created by imagecreate(), imagecreatefromjpeg(), imagecreatefrompng(), ...

setStampPosition ( X, Y) method is used to set stamp position on image.
X possible values are transparentWatermarkOnLeft, transparentWatermarkOnCenter and 
transparentWatermarkOnRight, Y possible values are transparentWatermarkOnTop, transparentWatermarkOnMiddle
and transparentWatermarkOnBottom


NOTES: 
It's IMPORTANT to save result of watermaks on disk: it's easy to retrieve 
an image from different versions of watermark by pixel color averages.

Transparent color is grey (#RGB=#808080)

transparentWatermark class uses GD library .