Single page with huge figure [duplicate]

Question

I'm writing a paper and I want to insert a figure that should occupy a whole page. Moreover, the figure has small details, so I want to reduce the margins in that page. On the other pages I'd like to use amsart margin settings. I reproduce my attempt below. The problem with that implementation is that the page is not "floating", so there is a big empty area in the preceding page.

\documentclass[10pt,letter]{amsart}
\usepackage[marginratio=1:1,height=584pt,width=360pt,tmargin=117pt]{geometry}
\usepackage{lipsum}
\usepackage{graphicx}
\usepackage[font=small]{caption}
\begin{document}
\title{A note}
\author{me}
\maketitle
\section{Introduction}
\lipsum
See Figure~\ref{fig.main}.
\newgeometry{right=5mm, left=5mm} 
\begin{figure}
\centering
\includegraphics[width=\textwidth]{main_figure.pdf}
\caption{A huge figure.}\label{fig.main}
\end{figure}
\restoregeometry
\lipsum
\end{document}

Answer 1

See if the next solution is what you expect:

\documentclass[10pt,letter]{amsart}
\usepackage[marginratio=1:1,
            height=584pt,
            width=360pt,
            tmargin=117pt]{geometry}
\usepackage{graphicx}
\usepackage[font=small]{caption}
\usepackage[strict]{changepage}

%---------------- show page layout. don't use in a real document!
\usepackage{showframe}
\renewcommand\ShowFrameLinethickness{0.15pt}
\renewcommand*\ShowFrameColor{\color{red}}
%---------------------------------------------------------------%
\usepackage{lipsum}
\begin{document}
\title{A note}
\author{me}
\maketitle
\section{Introduction}
\lipsum[1]
See Figure~\ref{fig.main}.
    \begin{figure}[!h]
\begin{adjustwidth}{-\marginparwidth}{-\marginparwidth}
    \includegraphics[width=\linewidth, height=0.93\textheight]{example-image-duck}
    \caption{A huge figure.}\label{fig.main}
\end{adjustwidth}
    \end{figure}
\lipsum
\end{document}

(red lines indicate page layout)