\documentclass[10pt,a4paper,twoside,ngerman]{article}
\usepackage{fixltx2e}%% the official fixes for LaTeX2e
\usepackage[T1]{fontenc}
\usepackage[latin1]{inputenc}
\usepackage{afterpage}
\usepackage{graphicx}
\newlength{\Vertikal}
    \setlength{\Vertikal}{\topmargin}
    \addtolength{\Vertikal}{\headheight}
    \addtolength{\Vertikal}{\headsep}
    \addtolength{\Vertikal}{1in} % voffset
    \addtolength{\Vertikal}{-\paperheight}
    \addtolength{\Vertikal}{\baselineskip}

\newlength{\Horizontal}
    \setlength{\Horizontal}{\oddsidemargin}
\newcommand{\setHOffset}[1]{%
    \addtolength{\Horizontal}{#1} % hoffset
}
\makeatletter
    \def\myV{\strip@pt\Vertikal}
    \def\myH{\strip@pt\Horizontal}
    \def\paperWidth{\strip@pt\paperwidth}
    \def\paperHeight{\strip@pt\paperheight}
\makeatother
  \newcommand{\atext}{Lorem ipsum dolor sit amet, consectetuer
    adipiscing elit,
    sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna
    aliquam erat volutpat. }
  \newcommand{\moretext}{\atext\atext\atext\atext\atext\par}
  \newcommand{\all}{\moretext\moretext\moretext\moretext}
\newcommand{\printImage}[1]{%
  \afterpage{%
   \setlength{\unitlength}{1pt}     
   \thispagestyle{empty}     
   \begin{picture}(0,0)       
     \put(-\myH,\myV){%           
        \fbox{%
          \makebox(\paperWidth,\paperHeight){% 
            \includegraphics[width=\paperwidth]{#1}%
          }%
        }%
     }%
   \end{picture}
   \newpage%
  }%
}
\usepackage{babel}
\begin{document}
\all \all \all %only for demo

In the following ERT use the setHOffset to set the image in the right
horizontal way. 

The image lyx1.eps is also available for download on the help-pages.

\setHOffset{2in}

\printImage{lyx1}

\all \all \all %only for demo
\end{document}