I have an "old-school" artist friend who likes to draw on paper with a pencil (it's really a friend, not me

We usually scan his art (comicbook pages), enhance the JPG with Gimp and use Inkscape to make an SVG file.
I have to do extra steps to slice his work into panels (in Gimp) so I can have more control over the layout independently in Inkscape.
Is there a way to do this "slicing" within Inkscape so I can eliminate the extra work in Gimp? It would save a great amount of time and speed up our process.
thanks,
--iM