Put an image header in \documentclass{letter}

Is there is any possibility to put an image header in a letter class document? I can put a footer image and an image for my signature, but I want to put an image on the top of the letter.

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Welcome to TeX.sx! I took the liberty to rephrase your text a little bit. The way to was didn't sounded correct. I hope you don't mind. –  Martin Scharrer Jan 27 '12 at 13:41
+1 for accepting answers! –  karlkoeller Jul 2 '13 at 15:22

The letter class uses a page style called firstpage on the first page ...

\documentclass{letter}

\usepackage{graphicx}
\usepackage{fancyhdr}
\usepackage{geometry}
\usepackage{lipsum}

\pagestyle{plain}
\begin{document}%
\begin{letter}{}%
\opening{Dear Some Name,}
\lipsum[1-10]
\end{letter}%
\end{document}%

It turns out the firstpage page style is only used if \address has not been used. If address has been used, then the first page style is empty and you need to add

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Why is the logo in the first page missing when I add the command \address{}? –  hpesoj626 Aug 26 '12 at 10:29
@hpesoj626 see the edit, \address{} causes the page style of the first page to be empty. –  StrongBad Aug 28 '12 at 9:06
Okay, that works. Thanks a lot. –  hpesoj626 Aug 28 '12 at 9:31

This is an extract from an in-house class we got for typesetting letters. Simply you just include the image.

\documentclass{letter}
\usepackage{graphicx}
\makeatletter
\newif\if@xl@logo
\@xl@logofalse
\def\setlogo#1{\@xl@logotrue\gdef\xl@companylogo{#1}}
\setlogo{HSlogo}

\def\printlogo{%
\if@xl@logo
\includegraphics[width=.98\textwidth]{./\xl@companylogo}\par%
\fi
}

\AtBeginDocument{\printlogo}
\begin{document}

\end{document}