Probably not in Word. Ideally you would do this in a graphics app. But if
all you have is Word, insert the picture in a Word document and then use the
instructions at http://www.gmayor.com/extract_images_from_word.htm to
extract the image to a Web folder. There's a good chance it will be
extracted as a JPEG (at least, this has been my experience); if you *wanted*
it to be a JPEG, it would be a GIF.