[NTG-pdftex] \pdfximage : is there a transparency attribute or method ?

I am attempting to incorporate http://thai-an.co.uk/Resources/Graphics/thai-an-logo-no-phone.png as a background image in PdfTeX, and of course it is far too saturated to use as-is. While I could manipulate it in Photoshop or similar, I wonder if there is a more direct way whereby I can specify (say) its transparency in PdfTeX so as to effectively reduce its saturation ? Philip Taylor -- Not sent from my i-Pad, i-Phone, Blackberry, Blueberry, or any such similar poseurs' toy, none of which would I be seen dead with even if they came free with every packet of cornflakes.