[Bladerunner1962]

There is no batch downloader that I know of, there is Ember media manager that when you scrape a movie also scrapes the actor images into the movie folder.
Your best bet to get all the actor images is to select actor images from the main menu (down arrow) then switch to wall view as it shows the most actors, then while online slowly scroll through the pages and it will automatically download the images as you get to them,

Then after you have them all, you can export as single files and all actor images will be copied to there respective movie folders. That's the only fast way I know of.

Main Menu: you mean e.g. Movies and down arrow to Submenu? If yes: I did now so as you proposed and switched to wall view. But, there happens nothing. I don't see, that there happens any download
or that I see first images if I wait on the wall. The actors are always without images.