[O] Org-mode Beamer graphviz & images

[deadbrain]

Hi all org-mode gurus,
I am trying to generate a deck of slides using Emacs/org-mode /beamer &
some companion tools (graphviz & plantuml).
I have a problem to set the dimensions for the graphviz (or plantuml)
generated pictures.
Whatever the version used (tested 8.2.10-30 or 8.3-beta from git) and
whatever the option (ATTR_LATEX set) the TEX file generated does not
contain the right scaling options.

Here is a generated TEX file (very short) :
% Created 2015-02-09 Mon 21:54
\documentclass[presentation,smaller]{beamer}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{fixltx2e}
\usepackage{graphicx}
\usepackage{longtable}
\usepackage{float}
\usepackage{wrapfig}
\usepackage{rotating}
\usepackage[normalem]{ulem}
\usepackage{amsmath}
\usepackage{textcomp}
\usepackage{marvosym}
\usepackage{wasysym}
\usepackage{amssymb}
\usepackage{capt-of}
\usepackage{hyperref}
\tolerance=1000
\usetheme{Marburg}
\usecolortheme{}
\usefonttheme{}
\useinnertheme{}
\useoutertheme{}
\date{\today}
\title{Test ORG \& Graphviz}
\begin{document}

\maketitle
\begin{frame}{Outline}
\tableofcontents
\end{frame}


\section{Une section}
\label{sec-1}
\begin{frame}[label=sec-1-1]{Test graphviz}
\includegraphics[width=.9\linewidth]{graph-intro.png}
\end{frame}
% Emacs 24.4.1 (Org mode 8.3beta)
\end{document}




from this org document:

#+BEAMER_COLOR_THEME:
#+BEAMER_FONT_THEME:
#+BEAMER_HEADER:
#+BEAMER_INNER_THEME:
#+BEAMER_OUTER_THEME:
#+BEAMER_THEME: Marburg
#+OPTIONS:   H:2 toc:t
#+LATEX_CLASS: beamer
#+LaTeX_CLASS_OPTIONS: [presentation,smaller]
#+BEAMER_FRAME_LEVEL: 2
#+COLUMNS: %20ITEM %13BEAMER_env(Env) %6BEAMER_envargs(Args)
%4BEAMER_col(Col) %7BEAMER_extra(Extra)
#+TITLE: Test ORG & Graphviz

* Une section
** Test graphviz
#+ATTR_LATEX: :height 25cm
#+begin_src dot :file graph-intro.png :cmdline -Kdot -Tpng
digraph G{
node1 -> node2
node1 -> node3
node3 -> node4
node3 -> node5
}
#+end_src


Obviously I am doing something wrong , but what ?

Thanks for your help
Kind regards