\documentclass[english]{article}
\RequirePackage[a4paper,
left=23mm, right=23mm,
twoside=true,
footskip=2mm,
%top=51mm, bottom=51mm,
nohead]{geometry}
\usepackage{babel}
\usepackage[latin1]{inputenc}
\usepackage{t1enc}
\usepackage{aeguill}
\usepackage{graphicx}
%\usepackage{pdfpages}

\def\bigimg#1{\hspace{-0.05\textwidth}\includegraphics[width=1.05\textwidth]{#1}}
\def\Bigimg#1{\hspace{-0.13\textwidth}\includegraphics[width=1.2\textwidth]{#1}}
\def\img#1#2{{\begin{center}\includegraphics[width=#2\textwidth]{#1}\end{center}}}
\begin{document}
\thispagestyle{empty}

\mbox{}
\vskip -32mm
\Bigimg{header-small}

\end{document}