How to label an image inside tikz

Question

I want to label the images img1 and img2.. can i do that inside my \node? If yes, how??

\documentclass{article}

\usepackage{tikz}

\begin{document}

\begin{tikzpicture}
        \path (0,0) node(a) {\includegraphics[width=2cm] images/img1.png}};
        \path (1,6) node(b) {\includegraphics[width=2cm]{images/img2.png}};
        \path (9,6) node(c) {\includegraphics[width=2cm]{images/img3.png}};
        \path (10,0) node(d) {\includegraphics[width=2cm]{images/img4.png}};
        \draw[very thick,green] (a) -- (b) node [midway,right]{\parbox{4cm}{TLS Password Based\\ Authentication}};
        \draw[very thick,red] (b) -- (c) node [midway,above]{Certificate based Authentication};
        \draw[very thick,green] (c) --(d);
\end{tikzpicture}    
\end{document}

What i mean by label is that something like this..

\path (\x,\y) node(a) [rectangle, draw,thick] {This is a rectangle};

Something like this as shown in figureas "Alice", "Bob", SIP Proxy Server Domain" etc..

Answer 1

How about this:

\documentclass{article}
\usepackage{tikz}
\usepackage{lipsum}

\parindent0mm

\begin{document}

\begin{tikzpicture}
    \draw (-3,-1) rectangle (3,1) (-2,-2) rectangle (2,2);
    \node[below right] at (current bounding box.south west) {\textbf{Image 1: rectangles}};
\end{tikzpicture}

\lipsum[1]

\begin{tikzpicture}
    \draw (-3,-1) circle (1) (-2,-2) circle (2);
    \node[below right] at (current bounding box.south west) {\textbf{Image 2: circles}};
\end{tikzpicture}

\end{document}

---

Edit 1: Probably like this (the icon are taken from here):

\documentclass{article}
\usepackage{tikz}

\begin{document}

\begin{tikzpicture}
    \node (cal) at (0,0) {\includegraphics[scale=4]{Calendar2.png}};
    \node (dow) at (7,0) {\includegraphics[scale=1.7]{Downloads.png}};  
    \node (fol) at (7,7) {\includegraphics[scale=1.7]{Folder.png}};
    \node (emo) at (0,7) {\includegraphics[scale=1.7]{Emoticons.png}};

    \node[below right] at (emo.south west) {\textbf{Img 1:} Emoticon};
    \node[below right] at (fol.south west) {\textbf{Img 2:} Folder};
    \node[below right] at (cal.south west) {\textbf{Img 3:} Calendar};
    \node[below right] at (dow.south west) {\textbf{Img 4:} Downloads};
\end{tikzpicture}

\end{document}

Answer 2

[fr] est-ce cela que tu cherches?

[en] Is this what you are looking for?

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{positioning,fit,shapes}


\begin{document}

\begin{tikzpicture}

\node[label={[ below =3.5cm of  Alice]:Alice}](Alice) {\includegraphics{PC-Alice.png}};

\node[right=4cm of Alice,label={[ below =3.5cm of  bob]:Bob}](bob) {\includegraphics{Tel-Bob.png}};

\node[above = 3cm of Alice,label={[ below =4.5cm of  server1]:Server 1}] (server1) {\includegraphics{serveur.png}};

\node[above = 3cm of bob,label={[ below =4.5cm of  server2]:Server 2}] (server2) {\includegraphics{serveur.png}};

\node[fit=(Alice) (server1), draw,red,ellipse,inner sep=0pt]{};  
\node[fit=(bob) (server2), draw,red,ellipse]{};    
\end{tikzpicture}

\end{document}