In this panel of "Questionable Content"is the artist actually drawing the background for each panel or is the software allowing him to simply change the changing elements in the foreground?
Jeph usually draws a new background for each location and then reuses it and alters it a little each time he needs to use it. I don’t know if the different “zooms” and “pans” over the background require different ones though, I assume the zooms do, but the pans may be one long image. You could watch his livestream (he tweets on @jephjacques when he begins it) and watch him draw the comic for the night, he always records his drawing sessions.