How change the position of background and rotate it?

Question

I used 1 to set an image as background. But it is at the bottom of the page. My question is how can I change the position of the image and rotate it about 45 degrees? I want to put it at the center of the page.

Answer 1

For more control, I use everypage and tikz (or tikzpagenodes). Everypage runs before the page is shipped out, so it will be in the background without needing layers.

Don't forget to run it twice.

\documentclass{article}
\usepackage{tikz}
\usepackage{everypage}

\AddEverypageHook{\begin{tikzpicture}[remember picture,overlay]
  \node[rotate=45, inner sep=0pt, opacity=.5] at (current page.center) {\includegraphics{example-image}};
\end{tikzpicture}}

\usepackage{lipsum}%MWE only
\begin{document}
\lipsum[1-30]
\end{document}