Please see what I have written,when I need individual grid on each of picture inside my figure-array. In contrast to previews question Drawing a grid on array of images. Question now is why I can't use \subfloat before \includegraphics in this case? I want to since I need caption below each image. Also I guess it should be some solution to optimize this code, like to define new command and not write grid code on each element of array, since I have more arrays in original document.
\documentclass{article}
\usepackage{subfig}
\usepackage[demo]{graphicx}
\usepackage{tikz}
\begin{document}
\begin{figure}
\centering
\begin{tikzpicture}
\node[anchor=south west,inner sep=0] (image) at (0,0){\includegraphics[trim = 10mm 10mm 70mm 20mm,clip,scale=0.15]{image1}};
\begin{scope}[x={(image.south east)},y={(image.north west)}]
\draw[help lines,xstep=.1,ystep=.1] (0,0) grid (1,1);
\end{scope}
\end{tikzpicture}
\begin{tikzpicture}
\node[anchor=south west,inner sep=0] (image) at (0,0){\includegraphics[trim = 10mm 10mm 70mm 20mm,clip,scale=0.15]{image2}};
\begin{scope}[x={(image.south east)},y={(image.north west)}]
\draw[help lines,xstep=.1,ystep=.1] (0,0) grid (1,1);
\end{scope}
\end{tikzpicture}\\
\begin{tikzpicture}
\node[anchor=south west,inner sep=0] (image) at (0,0){\includegraphics[trim = 10mm 10mm 70mm 20mm,clip,scale=0.15]{image3}};
\begin{scope}[x={(image.south east)},y={(image.north west)}]
\draw[help lines,xstep=.1,ystep=.1] (0,0) grid (1,1);
\end{scope}
\end{tikzpicture}
\begin{tikzpicture}
\node[anchor=south west,inner sep=0] (image) at (0,0){\includegraphics[trim = 10mm 10mm 70mm 20mm,clip,scale=0.15]{image4}};
\begin{scope}[x={(image.south east)},y={(image.north west)}]
\draw[help lines,xstep=.1,ystep=.1] (0,0) grid (1,1);
\end{scope}
\end{tikzpicture}
\caption{Time evolution}
\end{figure}
\end{document}
