documentclass[compress,xcolor={usenames,dvipsnames,table},12pt]{beamer}

title{Title}
author{Author}
date{September 14th, 2018}

setbeamertemplate{background}{%
  includegraphics[width=paperwidth,height=paperheight]{background.jpg}
}


begin{document}

  begin{frame}
    titlepage
  end{frame}

end{document}