PNG as a background?

As a fan of both tikz and background, here's a version showing four different opacities:




            \node[opacity=\myopacity] {\includegraphics[scale=1]{avatar.png}};





enter image description here

You just have to run pdflatex twice for the transparency to kick in for your original tex source. The package actually prints out a message to say that when you run it the first time.