tikz cookbook

Drawing on an image with TikZ
http://tex.stackexchange.com/questions/9559/drawing-on-an-image-with-tikz

Drawing label on figure (using tikz)
\begin{tikzpicture}
            \node[anchor=south west,inner sep=0] at (0,0) {\includegraphics[trim={600px 200px 50px 200px},clip, width=1\linewidth]{images/DP_10150_simpleCombinedBasedOnDPlen.exe_scale1_blank/frm00001}};
            %\draw[white,fill=white] (0.0,0.0) rectangle (0.5,0.5);
            \node[minimum size=.6cm, fill=white,anchor=south west] at (0.0,0.0){а};        \end{tikzpicture}