Check for a valid file before using \includegraphics

Question

I know how to check if a given argument represents an existing file (see this question).

But is there also a possibility to check if this file can be included by \includegraphics?

What I want to achieve is a command that

• includes an image (and does some more things) if it can, but
• includes some kind of info box and adds an entry to a 'list of missing images' if the argument doesn't point to a (existing and valid) image file.

Answer 1

Second attempt

This here should do the same tests than \includegraphics. That means if will give yes if the graphics/file exists and if the extension can be handled be the engine (so tiger.eps will give different results with pdflatex and latex: (The code is from the definition of \Ginclude@graphics in graphics.sty).

\documentclass[]{article}
\usepackage{graphicx}

\makeatletter
\newif\ifgraphicexist

\catcode`\*=11
\newcommand\imagetest[1]{%
 \begingroup
 \global\graphicexisttrue
   \let\input@path\Ginput@path
  \filename@parse{#1}%
  \ifx\filename@ext\relax
    \@for\Gin@temp:=\Gin@extensions\do{%
      \ifx\Gin@ext\relax
        \Gin@getbase\Gin@temp
      \fi}%
  \else
    \Gin@getbase{\Gin@sepdefault\filename@ext}%
    \ifx\Gin@ext\relax
       \global\graphicexistfalse
       \def\Gin@base{\filename@area\filename@base}%
       \edef\Gin@ext{\Gin@sepdefault\filename@ext}%
    \fi
  \fi
  \ifx\Gin@ext\relax
         \global\graphicexistfalse
    \else 
       \@ifundefined{Gin@rule@\Gin@ext}%
         {\global\graphicexistfalse}%
         {}%
    \fi  
  \ifx\Gin@ext\relax 
   \gdef\imageextension{unknown}%
  \else
   \xdef\imageextension{\Gin@ext}%
  \fi 
 \endgroup 
 \ifgraphicexist
  \expandafter \@firstoftwo
 \else
  \expandafter \@secondoftwo
 \fi 
 } 
\catcode`\*=12
\makeatother 

\begin{document}

\imagetest{tiger}{Yes, \imageextension}{No, \imageextension}

\imagetest{tiger.eps}{Yes, \imageextension}{No, \imageextension}

\imagetest{fail}{Yes, \imageextension}{No, \imageextension}

\imagetest{failxxx.eps}{Yes, \imageextension}{No, \imageextension}

\imagetest{bib.bib}{Yes, \imageextension}{No, \imageextension}
\end{document}

Answer 2

it needs the full name of the file. You can scan the logfile for Imagefile to get all missing images files.

\documentclass{book}
\usepackage{graphicx}
\newcommand\IG[2][]{\IfFileExists{#2}
  {\includegraphics[#1]{#2}}
  {\fbox{File #2 doesn't exist}%
   \message{Imagefile #2 doesn't exist^^J}}}

\begin{document}    
\IG{foo}

\IG[width=3cm]{tiger.pdf}

\end{document} 

Answer 3

\documentclass[preview,border=12pt,varwidth]{standalone}
\usepackage{graphicx}

\newwrite\writer
\immediate\openout\writer=missing.txt\relax

\newcommand\IG[2][]{\IfFileExists{#2}
  {\includegraphics[#1]{#2}}
  {\immediate\write\writer{\unexpanded{#2\newline}}}}


\begin{document}    
\IG{foo.ext}

\IG[width=3cm]{example-image-a.pdf}

\IG{goo.eps}

\IG{hoo.png}


\section*{Missing Graphics}
\immediate\closeout\writer
\input{missing.txt}

\end{document}

Answer 4

I would like to share the final result from what I got on stackexchange. Maybe it is of use for someone ...

The following document implements a 'public' command printFigure that is to be placed within a floating environment (like figure in this example). It takes the same two arguments as \includegraphics.

If the given filename points to a valid image file the command behaves normally, but if it can't print the image it prints a colored box instead and colors the lof entry.

The point of this isn't mainly to notice missing image files (which is already quite handy because I manage everything with remote Git repositories and have to generate image file on each computer separately. More important is the option to enter images that aren't created yet, just to get the structure clearer while writing the document.

I will soon rerelease this as part of a package that manages music examples.

\documentclass[]{article}
\usepackage[export]{adjustbox}
\usepackage{caption}
\usepackage{xcolor}

\makeatletter
\newif\ifgraphicexist

\catcode`\*=11

\newcommand\ifvalidimage[1]{%
    \begingroup
    \global\graphicexisttrue
    \let\input@path\Ginput@path
    \filename@parse{#1}%
    \ifx\filename@ext\relax
    \@for\Gin@temp:=\Gin@extensions\do{%
        \ifx\Gin@ext\relax
        \Gin@getbase\Gin@temp
        \fi}%
    \else
    \Gin@getbase{\Gin@sepdefault\filename@ext}%
    \ifx\Gin@ext\relax
    \global\graphicexistfalse
    \def\Gin@base{\filename@area\filename@base}%
    \edef\Gin@ext{\Gin@sepdefault\filename@ext}%
    \fi
    \fi
    \ifx\Gin@ext\relax
    \global\graphicexistfalse
    \else 
    \@ifundefined{Gin@rule@\Gin@ext}%
    {\global\graphicexistfalse}%
    {}%
    \fi  
    \ifx\Gin@ext\relax 
    \gdef\imageextension{unknown}%
    \else
    \xdef\imageextension{\Gin@ext}%
    \fi 
    \endgroup 
    \ifgraphicexist
    \expandafter \@firstoftwo
    \else
    \expandafter \@secondoftwo
    \fi 
} 
\catcode`\*=12
\makeatother 

% Now define a command that colors a lof entry red.
% This is necessary because the parts in \DeclareCaptionListFormat
% are put in separate groups by LaTeX.
\DeclareRobustCommand{\colortwogroups}{\makeredaux\aftergroup\makeredaux}
\newcommand\makeredaux{\color{red}}

% Declare a caption list format for use with missing images
\DeclareCaptionListFormat{missingfig}{\colortwogroups#1 #2}

\newcommand{\printFigure}[2][]{%
    \ifvalidimage{#2}
    {% If we have a correct image file:

        \noindent
        % 'max width' courtesy of adjustbox
        \includegraphics[max width=\textwidth,#1]{#2}

    }%
    {% if we don't find an appropriate image:

        \bigskip
        % make the caption red (in the \listoffigures)
        \captionsetup{listformat=missingfig}%
        % print a box instead of the image
        \fcolorbox{red}{yellow}{%
            \parbox[c]{.7\textwidth}{~\\
                \textbf{\textsf{Missing image:}}\\
                #2\\
            }
        }

        \bigskip
    }
}

\begin{document}

\begin{figure}
    \printFigure{bsp1}
    \caption{A quite fancy music example}
\end{figure}

\begin{figure}
    \printFigure{bsp2}
    \caption{Another quite fancy music example}
\end{figure}

\listoffigures

\end{document}