\DeclareGraphicsExtensions ¶Synopses:
\DeclareGraphicsExtensions{comma-separated list of file extensions}
Declare the filename extensions to try. This allows you to specify the
order in which to choose graphic formats when you include graphic files
by giving the filename without the extension, as in
\includegraphics{functionplot}.
In this example, LaTeX will find files in the PNG format before PDF files.
\DeclareGraphicsExtensions{.png,PNG,.pdf,.PDF}
...
\includegraphics{lion} % will find lion.png before lion.pdf
Because the filename lion does not have a period, LaTeX uses
the extension list. For each directory in the graphics path
(see \graphicspath), LaTeX will try the extensions in the order
given. If it does not find such a file after trying all the directories
and extensions then it reports ‘! LaTeX Error: File `lion'
not found’. Note that you must include the periods at the start of the
extensions.
Because GNU/Linux and Macintosh filenames are case sensitive, the list of file extensions is case sensitive on those platforms. The Windows platform is not case sensitive.
You are not required to include \DeclareGraphicsExtensions in
your document; the printer driver has a sensible default. For example,
the most recent pdftex.def has this extension list.
.pdf,.png,.jpg,.mps,.jpeg,.jbig2,.jb2,.PDF,.PNG,.JPG,.JPEG,.JBIG2,.JB2
To change the order, use the grfext package.
You can use this command anywhere in the document. You can use it more
than once. Show its value with
\makeatletter\typeout{\Gin@extensions}\makeatother.