TikzAbsoluteGraphicsPos.tex

\documentclass[10pt]{article}
\usepackage[paperheight=20cm,paperwidth=20cm,top=0mm,bottom=0mm,left=0mm,right=0mm]{geometry}
\usepackage{tikz}
\usepackage{graphicx}
\usetikzlibrary{calc}
\begin{document}
\pagestyle{empty}
\begin{tikzpicture}[remember picture,overlay]
\node[anchor=north west,inner sep=0] at ($(current page.north west)+(25mm,-25mm)$) {
\fbox{\includegraphics[scale=1,trim=25mm 113.82833mm 112.5mm 25mm]{test-graphics.pdf}}
};
\end{tikzpicture}
\end{document}