How to get an image watermark in the bottom right corner document (background and tikz)?

Question

I have been trying to put an image in the bottom right corner in background of my document (title page excluded) and I have succeeded at putting a nicely centred water mark using the following code:

\documentclass[titlepage,a4paper,twocolumn]{article}
\usepackage{geometry}
\usepackage{graphicx}
\usepackage{tikz}

\usepackage{background}
\backgroundsetup{
    scale=0.5,
    firstpage=false,
    angle=0,
    opacity=0.15,
    contents=   {\begin{tikzpicture}[remember picture, overlay]
                    \node at (currentpage.southeast){\includegraphics{img/image.png}};
                \end{tikzpicture}}
}

\begin{document}
Some stuff for the title page. % where the image also shows up
\section{intro} % now the twocolumn starts
With a lot of text.

And then the rest of the five-page doc.

What am I overlooking?

Answer 1

The following code is based on eso-pic and put a watermark at the right-hand side lower corner. Everything is managed by tikz, eso-pic only adds the watermark on every page. If you want to stop a watermark from a page onward, you could also use \ClearShipoutPictureBG

\documentclass[12pt]{report}
\usepackage{tikz}
\usepackage{graphicx}
\usepackage{eso-pic}
\usepackage{kantlipsum}

%% Define watermarks
\newsavebox\WM
\savebox\WM{%
  \begin{tikzpicture}[overlay]   % remember picture
    \node (WD) [anchor=south east, xshift=-5mm, yshift=5mm, opacity=0.25]
    at (current page.south east)
      {\includegraphics[width=0.3\paperwidth]{example-image}};
  \end{tikzpicture}}

%% Title
\title{The Title}
\author{Firstname Surname}
\date{}


\begin{document}
\maketitle

\AddToShipoutPictureBG{\usebox\WM} % Start watermarks from here onward
\kant
\end{document}

Answer 2

Similar to Celdor solution but without using TikZ

\documentclass[12pt]{report}
\usepackage{graphicx}
\usepackage{eso-pic}
\usepackage{kantlipsum}

%% Title
\title{The Title}
\author{Firstname Surname}
\date{}

\AddToShipoutPictureBG{%
    \AtPageLowerLeft{%
        \put(\LenToUnit{\paperwidth-25mm}),\LenToUnit{5mm}){\includegraphics[width=2cm]{example-image-a}}%
    }}%

\begin{document}
\maketitle

\kant
\end{document}