Prefix "Figure" and giving reference to figures

Question

Is it possible to adjust the font size of the prefix Figure when captioning an included image? Furthermore, is it possible to refer to a picture in a meaningful way without using a caption; I tried but no number was attributed to the figure I get double ?? instead. I am using the package \hypcap by the way.

Thanks

MWE:

\documentclass{beamer}

\mode<presentation> {
}
\makeatletter
\let\insertsupervisor\relax
\newcommand\supervisortitle{Supervisor}
\mode<all>
{
    \newcommand\supervisor[1]{\def\insertsupervisor{#1}}
    \titlegraphic{}
}
\defbeamertemplate*{title page}{supdefault}[1][]
{
    \vbox{}
    \vfill
    \begingroup
    \centering
    \begin{beamercolorbox}[sep=8pt,center,#1]{title}
        \usebeamerfont{title}\inserttitle\par%
        \ifx\insertsubtitle\@empty\relax%
        \else%
        \vskip0.25em%
        {\usebeamerfont{subtitle}\usebeamercolor[fg]{subtitle}\insertsubtitle\par}%
        \fi%     
    \end{beamercolorbox}%
    \vskip1em\par
    \begin{beamercolorbox}[sep=8pt,center,#1]{author}
        \usebeamerfont{author}\insertauthor
    \end{beamercolorbox}
    \ifx\insertsupervisor\relax\relax\else
    \begin{beamercolorbox}[sep=8pt,center,#1]{author}
        \usebeamerfont{author}\supervisortitle:~\insertsupervisor
    \end{beamercolorbox}\fi
    \begin{beamercolorbox}[sep=8pt,center,#1]{institute}
        \usebeamerfont{institute}\insertinstitute
    \end{beamercolorbox}
    \begin{beamercolorbox}[sep=8pt,center,#1]{date}
        \usebeamerfont{date}\insertdate
    \end{beamercolorbox}\vskip0.5em
    {\usebeamercolor[fg]{titlegraphic}\inserttitlegraphic\par}
    \endgroup
    \vfill
}
\setbeamertemplate{title page}[supdefault][colsep=-4bp,rounded=true,shadow=\beamer@themerounded@shadow]\makeatother

\usepackage{graphicx} % Allows including images
\usepackage{booktabs} % Allows the use of \toprule, \midrule and \bottomrule in tables
\usepackage[utf8]{inputenc}
\usepackage{color}
\usepackage{hyperref}
\usepackage{siunitx}
\usepackage{hypcap}
\usepackage{amsmath}
\usepackage{pgf}
\usepackage[font={scriptsize}]{caption}
\usetheme{CambridgeUS}
\usecolortheme{seagull}
\setbeamertemplate{bibliography item}[text]
\begin{document}
\begin{frame}
    \frametitle{Cooling power measurements}
    \begin{columns}[c]
        \column{.5\textwidth}
        \begin{figure}
            \vspace{-.5cm}
            \includegraphics[width=.9\linewidth]{fig5a.png}\label{fig:5a}
        \end{figure}
        \footnotesize
        \begin{enumerate}
            \item He-Rb mixture with 200 bar He
            \item About 5 mW of cooling power
        \end{enumerate}
        \column{.5\textwidth}
        \begin{figure}
            \vspace{-.5cm}
            \includegraphics[width=.9\linewidth]{fig5b.png}\label{fig:5b}
        \end{figure}
        \footnotesize
        \begin{enumerate}
            \item Ar-Rb mixture with 230 bar Ar
            \item Order of magnitude larger CP
        \end{enumerate}
    \end{columns}
    \footnotesize
    \begin{itemize}
        \centering
        \item Expected cooling power red crosses
        \item Observed deflection angle blue crosses
    \end{itemize}
\end{frame}
\begin{frame}
    \frametitle{Temperature Gradient}
    \footnotesize
    Using a heat transfer model \cite{24}, after a cooling time $t$, the expected temperature gradient profile is:
    \begin{equation}
        \frac{dT}{dr}=-\frac{P_{cool}}{2\pi \kappa}\frac{e^{-\alpha z}}{r}\left[ \exp\left(\frac{2r^2}{\omega^2}\right)-\exp\left(\frac{2r^2}{\omega^2-8Dt}\right)\right]
    \end{equation}
    \begin{description}
        \item[Cooling]Probe beam deflected towards the cooling beam\ref{fig:5a}
        \item[Heating]Probe beam deflected away from the cooling beam\ref{fig:5b}
    \end{description}
\end{frame}
\end{document} 

Answer 1

Figures that are numbered or referenced by number in a presentation is somewhat bizarre, since viewers don't get to flip through it the way one would in an article. However, some presentations may be distributed to viewers (like in a classroom environment where students get to download presentations by the instructor).

Here's one option by using \figcaption[*][<opt>]{<text>} which shows a figure caption in the text with title <text> (and prefix; the starred version removes the prefix). Additionally, [<opt>] can be used to adjust the way the reference is named. The references in the below MWE should explain possible usages:

\documentclass{beamer}
\let\Tiny\tiny% http://tex.stackexchange.com/q/58087/5764
\usepackage{xparse}
\makeatletter
\NewDocumentCommand{\figcaption}{s o m}{%
  \par\IfBooleanF{#1}{\refstepcounter{figure}}% Step figure counter
  {\footnotesize\IfBooleanF{#1}{\alert{Figure~\thefigure}: }#3\par}%
  \xdef\@currentlabelname{\IfNoValueTF{#2}{#3}{#2}}%
}
\makeatother

\mode<presentation> {
}
\makeatletter
\let\insertsupervisor\relax
\newcommand\supervisortitle{Supervisor}
\mode<all>
{
    \newcommand\supervisor[1]{\def\insertsupervisor{#1}}
    \titlegraphic{}
}
\defbeamertemplate*{title page}{supdefault}[1][]
{
    \vbox{}
    \vfill
    \begingroup
    \centering
    \begin{beamercolorbox}[sep=8pt,center,#1]{title}
        \usebeamerfont{title}\inserttitle\par%
        \ifx\insertsubtitle\@empty\relax%
        \else%
        \vskip0.25em%
        {\usebeamerfont{subtitle}\usebeamercolor[fg]{subtitle}\insertsubtitle\par}%
        \fi%     
    \end{beamercolorbox}%
    \vskip1em\par
    \begin{beamercolorbox}[sep=8pt,center,#1]{author}
        \usebeamerfont{author}\insertauthor
    \end{beamercolorbox}
    \ifx\insertsupervisor\relax\relax\else
    \begin{beamercolorbox}[sep=8pt,center,#1]{author}
        \usebeamerfont{author}\supervisortitle:~\insertsupervisor
    \end{beamercolorbox}\fi
    \begin{beamercolorbox}[sep=8pt,center,#1]{institute}
        \usebeamerfont{institute}\insertinstitute
    \end{beamercolorbox}
    \begin{beamercolorbox}[sep=8pt,center,#1]{date}
        \usebeamerfont{date}\insertdate
    \end{beamercolorbox}\vskip0.5em
    {\usebeamercolor[fg]{titlegraphic}\inserttitlegraphic\par}
    \endgroup
    \vfill
}
\setbeamertemplate{title page}[supdefault][colsep=-4bp,rounded=true,shadow=\beamer@themerounded@shadow]
\makeatother

\usepackage{graphicx} % Allows including images
\usepackage{booktabs} % Allows the use of \toprule, \midrule and \bottomrule in tables
\usepackage[utf8]{inputenc}
\usepackage{xcolor,amsmath,pgf,siunitx}
\usepackage{hyperref}
\usepackage{hypcap}
\usetheme{CambridgeUS}
\usecolortheme{seagull}
\setbeamertemplate{bibliography item}[text]
\begin{document}
\begin{frame}
    \frametitle{Cooling power measurements}
    \begin{columns}[c]
        \column{.5\textwidth}
        \begin{figure}
            \vspace{-.5cm}
            \includegraphics[width=.9\linewidth]{example-image-a}
            \figcaption{ABC}\label{fig:5a}
        \end{figure}
        \footnotesize
        \begin{enumerate}
            \item He-Rb mixture with 200 bar He
            \item About 5 mW of cooling power
        \end{enumerate}
        \column{.5\textwidth}
        \begin{figure}
            \vspace{-.5cm}
            \includegraphics[width=.9\linewidth]{example-image-b}
            \figcaption*{BCD}\label{fig:5b}
        \end{figure}
        \footnotesize
        \begin{enumerate}
            \item Ar-Rb mixture with 230 bar Ar
            \item Order of magnitude larger CP
        \end{enumerate}
    \end{columns}
    \footnotesize
    \begin{itemize}
        \centering
        \item Expected cooling power red crosses
        \item Observed deflection angle blue crosses
    \end{itemize}
\end{frame}
\begin{frame}
    \frametitle{Temperature Gradient}
    \footnotesize
    Using a heat transfer model \cite{24}, after a cooling time $t$, the expected temperature gradient profile is:
    \begin{equation}
        \frac{dT}{dr}=-\frac{P_{cool}}{2\pi \kappa}\frac{e^{-\alpha z}}{r}\left[ \exp\left(\frac{2r^2}{\omega^2}\right)-\exp\left(\frac{2r^2}{\omega^2-8Dt}\right)\right]
    \end{equation}
    \begin{description}
        \item[Cooling]Probe beam deflected towards the cooling beam (see Figure~\ref{fig:5a})
        \item[Heating]Probe beam deflected away from the cooling beam (see \hyperlink{fig:5b}{\nameref{fig:5b}})
    \end{description}
\end{frame}
\end{document}