UK TeX FAQ -- question label unkgrfextn

### “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}

`grffile.sty`
  Distributed as part of the Oberdiek collection macros/latex/contrib/oberdiek (or browse the directory); catalogue entry

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