\usetikzlibrary{calc,trees,positioning,arrows,chains,shapes.geometric,%
decorations.pathreplacing,decorations.pathmorphing,shapes,%
matrix,shapes.symbols,plotmarks,decorations.markings,shadows,backgrounds}

\newcommand{\width}{6cm}
\newcommand{\vdisp}{6cm}

\begin{tikzpicture}
  \node[inner sep=0] at (0,0) {\includegraphics[width=\width]{Slices}};
  \node[inner sep=0] at (\width+.5cm,0) {\includegraphics[width=\width]{Tiles}};
  \node[inner sep=0] at (2*\width+1cm,0) {\includegraphics[width=\width]{WPP}};
\end{tikzpicture}