Unknown graphics extension

The LaTeX graphics package deals with several different types of DVI (or other) output drivers; each one of them has a potential to deal with a different selection of graphics formats. The package therefore has to be told what graphics file types its output driver knows about; this is usually done in the ‹driver›def file corresponding to the output driver you’re using.

The error message arises, then, if you have a graphics file whose extension doesn’t correspond with one your driver knows about. Most often, this is because you’re being optimistic: asking dvips to deal with a png file, or pdfTeX to deal with a eps file: the solution in this case is to transform the graphics file to a format your driver knows about.

If you happen to know that your device driver deals with the format of your file, you are probably falling foul of a limitation of the file name parsing code that the graphics package uses. Suppose you want to include a graphics file home.bedroom.eps using the dvips driver; the package will conclude that your file’s extension is bedroom.eps, and will complain.

The grffile package deals with the last problem (and others — see the package documentation); using the package, you may write:

\usepackage{graphicx}
\usepackage{grffile}
...
\includegraphics{home.bedroom.eps}

or you may even write

\includegraphics{home.bedroom}

and graphicx will find a eps or pdf (or whatever) version, according to what version of (La)TeX you’re running.

If for some reason you can’t use grffile, you have three unsatisfactory alternatives:

• Rename the file — for example home.bedroom.eps→ home-bedroom.eps
• Mask the first dot in the file name:

   \newcommand*{\DOT}{.}
   \includegraphics{home\DOT bedroom.eps}
  

• Tell the graphics package what the file is, by means of options to the \includegraphics command:

   \includegraphics[type=eps,ext=.eps,read=.eps]{home.bedroom}
  

FAQ ID: Q-unkgrfextn