Beam background switching

Question

I am trying to transfer a LaTeX / LyX presentation to a document labeled Beamer.

On some slides, I pause the background image (which has the logos of the funding authorities) to make more room for code output.

I previously did this with the following command:

\bgroup
\usebackgroundtemplate{\includegraphics[width=\paperwidth]{background.png}}
\begin{frame}[plain]
Some text here!}
\end{frame}
\egroup

I tried something like this (which doesn't work):

\bgroup
\pgfdeclareimage[width=\paperwidth]{empty}{Template_blank.png}
\usebackgroundtemplate{\pgfuseimage{empty}}

## New Slide

some text
\egroup

Any ideas?