One option would be to use the background
package to place the image as a background image; the geometry
package can be used to adjust the text area. A little example:
\documentclass{article}
\usepackage[tmargin=2.5cm,lmargin=2.5cm,rmargin=2.5cm,bmargin=2.5cm]{geometry}
\usepackage{graphicx}
\usepackage{background}
\usepackage{fourier}
\usepackage{lipsum}
\backgroundsetup{scale=1,angle=0,opacity=1,contents={\includegraphics[scale=1]{border}}}
\begin{document}
\lipsum[1-20]
\end{document}
An image of the first page of the resulting document:
Here's the code I used toproduce the border used:
\documentclass{article}
\usepackage[dvipsnames]{xcolor}
\usepackage[object=vectorian]{pgfornament}
\usetikzlibrary{calc}
\definecolor{mycolor}{cmyk}{0,0,0.1,0}
\pagestyle{empty}
\begin{document}
\color{mycolor}
\begin{tikzpicture}[remember picture,overlay]
\coordinate (a) at ( $ (current page.north west) + (1cm,-1cm)$);
\coordinate (b) at ( $ (current page.south west) + (1cm,1cm)$);
\coordinate (c) at ( $ (current page.south east) + (-1cm,1cm)$);
\coordinate (d) at ( $ (current page.north east) + (-1cm,-1cm)$);
\fill[Maroon] (current page.south west) rectangle ( $ (current page.north west) + (2cm,0) $);
\fill[Maroon] (current page.south east) rectangle ( $ (current page.north east) + (-2cm,0) $);
\fill[Maroon] (current page.north west) rectangle ( $ (current page.north east) + (0,-2cm) $);
\fill[Maroon] (current page.south west) rectangle ( $ (current page.south east) + (0,2cm) $);
\pgfornamenthline{a}{d}{north}{87}
\pgfornamenthline{b}{c}{south}{87}
\pgfornamentvline{a}{b}{west}{87}
\pgfornamentvline{c}{d}{east}{87}
\end{tikzpicture}
\end{document}