\documentclass[]{standalone}
\input{./tikzpreamble}
\begin{document}
    \begin{tikzpicture}
        \node[anchor=south west,inner sep=0] (image) at (0,0) {\includegraphics[width=\textwidth]{../pics/poweritv2_teststand_2_1.jpg}};
        \begin{scope}[x={(image.south east)},y={(image.north west)}]
            \draw[green, fill=green, fill opacity=.2, ultra thick, rounded corners] (.44, .85) rectangle (.64, .9);
            \draw[green, fill=green, fill opacity=.2, ultra thick, rounded corners] (.54, .12) rectangle (.35, .07);
            \draw[green, fill=green, fill opacity=.2, ultra thick, rounded corners] (.61, .7) rectangle (.40, .15);
            \draw[green, ultra thick, ->] (.5, .70) -- (.5, .85);
            \draw[green, ultra thick, ->] (.5, .15) -- (.5, .12);

            \draw[blue, fill=blue, fill opacity=.2, ultra thick, rounded corners] (.15, .25) rectangle (.08,.19);
            \draw[blue, fill=blue, fill opacity=.2, ultra thick, rounded corners] (.86, .71) rectangle (.94,.79);
            \draw[blue, fill=blue, fill opacity=.2, ultra thick, rounded corners] (.67, .13) rectangle (.77,.83);
            \draw[blue, ultra thick, ->] (.77, .75) -- (.86,.75);
            
            \draw[red, fill=red, fill opacity=.2, ultra thick, rounded corners] (.85, .24) rectangle (.93,.18);
            \draw[red, fill=red, fill opacity=.2, ultra thick, rounded corners] (.13, .71) rectangle (.06,.78);
            \draw[red, fill=red, fill opacity=.2, ultra thick, rounded corners] (.33, .14) rectangle (.22,.82);
            \draw[red, ultra thick, ->] (.22, .75) -- (.13,.75);

            \draw[blue, ultra thick, ->] (.67, .55) -| (.11,.25);
            \draw[red, ultra thick, ->] (.33, .45) -| (.89,.24);

            \draw[magenta, fill=magenta, fill opacity=.2, ultra thick, rounded corners] (.04, .8) rectangle (.14, .9);
            \draw[magenta, ultra thick, ->] (.14, .85) -| (.43, .70);
        \end{scope}
    \end{tikzpicture}
\end{document}