I'm trying to draw a diagram with pictures with TikZ. I know that people can direct use \includegraphics within a node so that the picture will be placed there. My question is, how do I generate a rectangle-shaped node and place 2 (or more) picture in it, pictures should be placed from top to bottom instead of from left to right (what I get when simply use 2 \includegraphics).
Here is an example, consider the top picture called top_pic.png, and bottom called botton_pic.png (another question: how do I place the transform symbol like in picture?)





inner sepvalue, e.g.\matrix [draw,inner sep=3mm] { .... If you want to change the distance between the images and the symbol, modify therow sep, e.g.\matrix [draw,inner sep=3mm,row sep=3mm] {.... – Torbjørn T. Apr 12 '18 at 16:16\includegraphics[width=5cm]{filename}as in my example. You can set the width of both images to the same length by adding\setkeys{Gin}{width=5cm}between\begin{tikzpicture}and\matrix, and using just\includegraphics{filename}. That said, you can of course just put the wholetikzpicturein a\scaleboxor\resizebox, but you'll probably have to change the length andline widthof the\drawthat makes the symbol in the middle so that it fits, so I would change the size of the images. – Torbjørn T. Apr 13 '18 at 18:35