Key features of "A-PDF Watermark":

Support text and image watermark
Support text watermark with macro (dynamic text)
Support image watermark with various image formats (eg. JPEG, GIF, TIF, TIFF, PCX, PNG, TGA, ICO, BMP, JP2 image formats)
Support watermark to any position in the page, includes header, center and footer
Using margins, watermark can be placed in the exact position or tile to pages.
Rotate watermark in any angle
Support opacity (transparent watermark) for text and images
Support standard font and true type font, font size, text color, text style
Support true type font embedded or not
Watermark can be placed on top or background of page