I have been using

\usepackage{wallpaper}
\ULCornerWallPaper{0.1}{image.jpg}


I wonder if there is a way to add a hyperlink to the image so that by clicking on the image, a URL opens.

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Sorry Marco. I have not. –  Reza Mar 9 '13 at 17:51

Based on the given definition of \ULCornerWallPaper by wallpaper I would define a new command. This new command has an extra mandatory argument. Making the picture "clickable" is done by the command \href.

The package mwe provides the example picture and loads also blindtext for filling text.

\documentclass{article}
\usepackage{mwe}
\usepackage{wallpaper}
\usepackage{hyperref}
\AtPageLowerLeft{%
\parbox[b][\paperheight]{#1\paperwidth}{\href{#2}{%
\includegraphics[width=#1\paperwidth,height=#1\paperheight,%
keepaspectratio]{#3}}%
\vfill%
}
}
}
}