Available in pre-release 3.7
Usage: SumatraPDF extract [options] file.pdf [object numbers]
You can use SumatraPDF info to get a list of image, font etc. objects present in a PDF file.
You can then use SumatraPDF extract to save image objects to a file.
For example SumatraPDF info -I returned:
Images (73):
        1       (8 0 R):        [ DCT ] 1280x1781 8bpc ICC (3 0 R)
(8 0 R) is object number of the page with the image.
(3 0 R) is object number of the image.
SumatraPDF extract file.pdf 3 will save image with object number 3 as image-3.jpg.

All options #

Usage: SumatraPDF extract [options] file.pdf [object numbers]
  -p      password
  -r      convert images to rgb
  -a      embed SMasks as alpha channel
  -N      do not use ICC color conversions