Adding a background picture to the first page and last page

Question

Hi I was just wondering on how I could add a background picture to the last page and first page?

I want one page without anything but the picture and a last page.

\documentclass[12pt]{extarticle}
\documentclass[parskip]{scrbook}
\usepackage{tikz}
\usetikzlibrary{calc,shadows}
\usepackage{lipsum}
\usepackage{lmodern}
\newtheorem{theorem}{Theorem}
\newtheorem{corollary}{Corollary}
\newtheorem*{definition}{Definition}
\newtheorem*{example}{Example}
\newtheorem*{note}{Note}
\newtheorem{exercise}{Exercise}
\newcommand{\bproof}{\bigskip {\bf Proof. }}
\newcommand{\eproof}{\hfill\qedsymbol}
\newcommand{\Disp}{\displaystyle}
\newcommand{\qe}{\hfill\(\bigtriangledown\)}
\setlength{\columnseprule}{1 pt}

\backgroundsetup{
 scale=1,
 angle=0,
 opacity=1,  
 contents={\includegraphics[width=\paperwidth,height=\paperheight] 
 {test.png}}

\begin{document}




\newpage

\section{Temporary}
\subsection{Fractional integrals}
\begin{exercise} Solve
\begin{equation} \int^\infty_0\frac{dx}{x\left(1+x^2\right)}
\label{eq:Pn}\end{equation}
\end{exercise}
\end{document}

This just adds the picture to all the pages. How can I restrict it to just doing it on two blank pages?

Thanks in advance.