Using Tikz to position a background image in mini page

Question

I'd like to use tikz to position a graphic at the lower right hand corner of a minipage. I've gotten this far (this isn't quite an MWE, since it depends on a locally available imagefile).

\documentclass{article}

\usepackage{lipsum}%
\usepackage{fullpage}%
\usepackage{tikz}%
\usepackage{graphicx}%

\begin{document}

\begin{minipage}{.5\textwidth}

\begin{tikzpicture}[overlay]
  \node{\includegraphics{imagefile}};
\end{tikzpicture}

{\Large\bfseries Title}%

{\em Subtitle}%
\begin{flushleft}
  \lipsum[1]
\end{flushleft}
\end{minipage}

\end{document}

That gets me here (with a suitable image for the "7"):

What I'd like, ultimately, is something like this:

Answer 1

Put the content of minipage inside a node. You can get rid of minipage and use node itself.

\documentclass{article}

\usepackage{lipsum}%
\usepackage{fullpage}%               %% use geometry instead
\usepackage{tikz}%
\usepackage{graphicx}%

\begin{document}

\begin{tikzpicture}
\node[inner sep=0pt,outer sep=0pt,text width=0.5\textwidth](a){%
{\Large\bfseries Title}\par%
\emph{Subtitle}%
\begin{flushleft}
  \lipsum[1]
\end{flushleft}
};
\node[scale=12,anchor=south east,inner sep=0pt,outer sep=0pt,opacity=0.5,font=\sffamily\bfseries,text=gray] at (a.south east){7};
\end{tikzpicture}

\end{document}

Answer 2

I don't think TikZ is needed. There may be easier ways of doing this but I'd go with (something like)...

\documentclass[varwidth, border=.75in]{standalone}

\usepackage{lipsum}
\usepackage{xcolor}
\usepackage{graphicx}
\begin{document}

{\Large\bfseries Title}

\emph{Subtitle}
\vskip1ex
\valign{&\vfil#\cr
\hsize=0pt
\rlap{\hskip0.4\textwidth\scalebox{6}{\Huge\sffamily\bfseries\textcolor{gray!50}{7}}}
\cr
\hsize=0.5\textwidth
\flushleft
\lipsum[4]
\cr}

\end{document}