biblatex: reduce font size citation mark

Question

How can I reduce the font size of the citation mark (using biblatex)?

An identical question was asked before, but, alas, it does not seem to work for me.

Consider the following MWE:

% arara: pdflatex
% arara: biber
% arara: pdflatex
% arara: pdflatex

\documentclass{beamer}

\usepackage{filecontents}
\begin{filecontents}{\jobname.bib}
@article{greenwade93,
    author  = "George D. Greenwade",
    title   = "The {C}omprehensive {T}ex {A}rchive {N}etwork ({CTAN})",
    year    = "1993",
    journal = "TUGBoat",
    volume  = "14",
    number  = "3",
    pages   = "342--351"
}
@book{goossens93,
    author    = "Michel Goossens and Frank Mittelbach and Alexander Samarin",
    title     = "The LaTeX Companion",
    year      = "1993",
    publisher = "Addison-Wesley",
    address   = "Reading, Massachusetts"
}
\end{filecontents}

\usepackage[backend=biber,natbib=true,style=alphabetic,citestyle=alphabetic]{biblatex}
\addbibresource{\jobname.bib}

% https://tex.stackexchange.com/questions/6953/biblatex-changing-the-font-of-citation-marks-and-the-references
% does not seem to work...
\renewcommand*{\citesetup}{%
    \small
    \biburlsetup
    \frenchspacing}
%or: \appto{\citesetup}{\footnotesize}

\begin{document}

\begin{frame}
Lorem ipsum~\citep{goossens93}.
Dolor sit amet~\citet{greenwade93}.
\end{frame}

\begin{frame}
\printbibliography
\end{frame}

\end{document}

The citation marks look the same size as the rest of the text, not smaller ...

Answer 1

At first you need \addbibresource{\jobname.bib} The extension is needed. However, instead of \small use \tiny and you'll see the font change. \small is often difficult to see because it is only a bit smaller than \normalsize