LaTeX Beamer frame environment with image background

tex

% This beamer environment provides a simple way to make slides with full-size images
%
% Usage:
%       \begin{imageframe}[keepaspectratio,width=\paperwidth]{bg_image.jpg}
           Here comes my slide content
        \end{imageframe}
%
% The environment scales the image to fit the slide by default in a way that ensures the
% entire picture is visible. That is usually not what you want. Use the optional parameter 
% to scale it as needed. Some common options are:
%
%   1) Scale to width:  keepaspectratio,width=\paperwidth
%   2) Scale to height: keepaspectratio,height=\paperheight
%   3) Squeeze to fit:  width=\paperwidth,height=\paperheight
%
\newenvironment{imageframe}[2][keepaspectratio,width=\paperwidth,height=\paperheight]
{%
  \begingroup%
  \setbeamertemplate{navigation symbols}{}%
  \usebackgroundtemplate{\includegraphics[#1]{#2}}%
  \begin{frame}[plain]%
}{%
  \end{frame}%
  \endgroup%
}