Latex: Skaalaa kuva pienemmäksi, mutta ei suuremmaksi


\usepackage{graphicx}
\usepackage{calc}

\newlength{\imgwidth}

%usage \scalegraphics{image_file}

\newcommand\scalegraphics[1]{%
\settowidth{\imgwidth}{\includegraphics{#1}}%
\setlength{\imgwidth}{\minof{\imgwidth}{\textwidth}}%
\includegraphics[width=\imgwidth]{#1}%
}