[Tex/LaTex] Background image does not cover the entire page

backgroundsbeamergraphics

My title page has a background image. However, when the presentation has sections (that create a navigation bar), there is a white box on top of the image. How can I get rid of it?

\documentclass[14pt]{beamer}   % 
\graphicspath{ {./graphics/} }
\mode<presentation>
{
  \usetheme{Warsaw}
  \usecolortheme{wolverine}
  \setbeamercovered{transparent}
}
\setbeamertemplate{navigation symbols}{}%remove navigation symbols

\begin{document}
{
\setbeamertemplate{headline}{}
\setbeamertemplate{footline}{}
\usebackgroundtemplate{\includegraphics[width=\paperwidth,height=\paperheight]{square-land-background.jpg}}%

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


\section{Introduction}
\begin{frame}{a}
\end{frame}


\section{first part}
\begin{frame}{b}
\end{frame}


\end{document}

I tried both solutions to this question: Beamer: Removing headline and its space on a single frame (for plan), but keeping the footline but they did not work.

Best Answer

A native beamer solution without additional packages:

\documentclass[14pt]{beamer} 
\usetheme{Warsaw}
\usecolortheme{wolverine}
\setbeamercovered{transparent}

\setbeamertemplate{navigation symbols}{}%remove navigation symbols

\begin{document}
{
\setbeamertemplate{headline}{\vskip\headheight}
\setbeamertemplate{footline}{}
\usebackgroundtemplate{\includegraphics[width=\paperwidth,height=\paperheight]{example-image}}%
\begin{frame}{}
\end{frame}
}


\section{Introduction}
\begin{frame}{a}
\end{frame}


\section{first part}
\begin{frame}{b}
\end{frame}


\end{document}

enter image description here

Related Question