Two images one on the other

Question

I have two picture, one (Image 1) is the big one while the other (Image 2) is the small one that is a detail of the big one. I would like to do something like the zoom option (with tikzpicture) but instead to have the zoomed image image I just want to see the other image. Everything inside a figure with its caption.

I made an example in case is difficult to understand what I want to do. Image 1 is my main image, the cross represents the schematised detail that is explained with Image 2. The two images are two .png.

Is it possible?

Answer 1

Starting point. Now, you only need to connect the other anchors and decide the right position for the squares.

\documentclass{report}
\usepackage{tikz}
\usepackage{graphicx}
\usepackage{lipsum}
\begin{document}
\lipsum[1]
\begin{figure}[h]\centering
\begin{tikzpicture}
\node[draw] (one) at (0,0){\includegraphics[width=6cm]{example-image-a}};
\node[anchor=north,draw,inner sep=0pt] (two) at ([xshift=-1cm]one.north west){\includegraphics[width=1cm]{example-image-b}};
\node[draw] (rect) at (-1,0){};
\draw (two.south east) -- (rect.south west);
\end{tikzpicture}
\caption{text}
\end{figure}

\lipsum[2]
\end{document}

Answer 2

A solution using path picture to clip the zoom.

And as @Sigur said 'Starting point. Now, you only need to connect the other anchors and decide the right position for the' circles.

\documentclass[a4paper, 12pt]{article}
\usepackage{mwe}
\usepackage{tikz}

\begin{document}

    \begin{figure}[h!]
        \centering
        \includegraphics[width=.7\linewidth]{example-image}
        \caption[Text for the list of figures]{Text under the figure}
        \label{fig:theReference0}
    \end{figure}

    \begin{figure}[h!]
        \centering
        \begin{tikzpicture}
            [path image/.style={path picture={\node at (path picture bounding box.center) {\includegraphics[height=3cm]{#1}};}}]

            \node (img) {\includegraphics[width=.7\linewidth]{example-image}};
            \node (c1) [draw, circle, red, text width=.7cm] at (img.center) {};
            \draw [red] (c1.east) -- (img.east);
            \draw [path image=example-image-a,draw=red,thick] (img.east) circle (2cm);
        \end{tikzpicture}
        \caption[Text for the list of figures]{Text under the figure}
        \label{fig:theReference}
    \end{figure}
\end{document}

Answer 3

With picture environment:

\documentclass{article}

\usepackage{graphicx}

\begin{document}

\noindent%
\setlength{\unitlength}{\textwidth}%
\begin{picture}(1,0.5)%
    \put(0.3,0){\includegraphics[width=.7\textwidth]{example-image}}%
    \put(0,0.33){\includegraphics[width=.2\textwidth]{example-grid-100x100bp}}%
    \put(0.0,0.33){\line(4,-1){.4}}
    \put(0.0,0.53){\line(4,-1){.4}}
    \put(0.2,0.33){\line(4,-1){.4}}
    \put(0.2,0.53){\line(4,-1){.4}}
    \put(0.4,0.23){\line(1,0){.2}}
    \put(0.4,0.43){\line(1,0){.2}}
    \put(0.4,0.23){\line(0,1){.2}}
    \put(0.6,0.23){\line(0,1){.2}}
\end{picture}%

\end{document}

Answer 4

I will share a sample code:

\documentclass{report}%report
% if you just want to create and use the figure in the original latex file to lower the compilation time like me, use standalone 
%\documentclass{standalone}
\usepackage{tikz}
\usepackage{graphicx}

\begin{document}
\begin{figure}[h]\centering
\begin{tikzpicture}
% 0,0 will be the distance from the inside small rectangle
\node[draw] (one) at (0,0){\includegraphics[width=6cm]{main_image.png}};
\node[anchor=north,draw,inner sep=0pt] (two) at ([xshift=1.55cm, yshift= -1.45cm]one.north east)
% bm: how far the zoom image should be, either west/east = right/left
{\includegraphics[width=3cm]{zoom_image.png}};
\node[draw = purple,minimum width=5.03cm,minimum height=1cm]
(rect) at (0.25,-1.45){};%(-2.2,-1.855){}; 
% draw, thick,minimum width=2cm,minimum height=2cm
% 
\draw [purple](two.south east) -- (rect.south west);
\draw [purple](two.north west) -- (rect.north east);
\end{tikzpicture}
%\caption{text}
\end{figure}
\end{document}