How to fake footnotes…

…at the bottom of a LaTeX figure page. Not very elegant, but here goes:

\usepackage{eso-pic}
...
\begin{figure}[p]
\includegraphics[width=\textwidth]{bigimage.jpg}
\caption{Some really important figure.\protect\footnotemark[1]}
\AtPageLowerLeft{\begin{minipage}{0.9\textwidth}
\vspace{0.8em}\rule{14em}{0.5px}\\
\hspace*{1em}\footnotesize{$^1$Ceci n'est pas une annotation.}
\end{minipage}}
\end{figure}
\addtocounter{footnote}{1}

Adjust the number by hand and fiddle with the spacing until it looks like a footnote.