I am trying to place a tikzpicture in a beamer frame on top of an image. In principle this should be easy, however changing the at(x,y) cordinate doesn't seem to have any effect at all.
My code is
\documentclass[demo]{beamer}
\usepackage{tikz}
\usetikzlibrary{decorations.pathmorphing}
\usetikzlibrary{decorations.markings}
\usetikzlibrary{%
calc,%
fadings,%
shadings%
}
\usetikzlibrary{arrows,shapes}
\usetikzlibrary{shapes.geometric,calc}
\usetikzlibrary{backgrounds,fit}
\usetikzlibrary{shadows}
\usetikzlibrary{snakes}
\usetikzlibrary{decorations.text}
\usetikzlibrary{positioning}
\usepackage{graphicx}
\begin{document}
\begin{frame}
\only<1>{\hspace*{-0.5cm}\includegraphics[width=1.1\columnwidth]{Stack_1}\begin{tikzpicture}
\node[align=center,color=gray!20, draw,fill=gray!20, text=red, cloud, cloud puffs=17, cloud puff arc=145, aspect=10,scale=0.5] at (-5cm,0cm) {\textbf{\large ``Fortunately our $\gamma$-flash has a constant shape''}};
\end{tikzpicture}}
\only<2>{\hspace*{-0.5cm}\includegraphics[width=1.1\columnwidth]{Stack_2}}
\end{frame}
\end{document}
Using at(0,0) gives me

which is the same output if I use at(10cm,10cm).
Any idea on why is this hapening and can it be fixed?

nodeinside atikzpicturehas no relation with the page coordinates. – Sigur May 11 '15 at 15:16\node<1>[options].... See also: http://tex.stackexchange.com/q/9559/32374 – darthbith May 11 '15 at 15:17