When using the tikzposter package, is it possible to add a background image?
I currently have a colour gradient, and would preferably like to keep this intact, and superpose the image on top of that.
The current document looks somewhat like this:
\documentclass{tikzposter}
\tikzposterlatexaffectionproofoff
%% colors
% title
\definecolor{backgroundcolortop}{RGB}{255,255,255}
\definecolor{backgroundcolormiddle}{RGB}{255,255,255}
\definecolor{backgroundcolorbottom}{RGB}{91,195,240}
\title{Ttile}
\author{{\LARGE Authors}\\{\normalsize email}}
\institute{{\Large Institute}}
\begin{document}
\titleblock[seperated=false, embedded=true]
%...
\end{document}
