gallery1.py

from marionette import Marionette, Actions, MultiActions
import time

#tested with 1.0.1 June 5
# setup boilerplate:
m = Marionette()
m.start_session()
m.switch_to_frame(2)

# Find the container element to dispatch scroll events to:
thumbnails = m.find_element("id", "thumbnails")

#scroll down
action = Actions(m)
action.press(thumbnails).move_by_offset(0, -20).wait(0.1).move_by_offset(0, -20).wait(0.1).move_by_offset(0, -20).wait(0.1).move_by_offset(0, -20).wait(0.1).move_by_offset(0, -20).wait(0.1).move_by_offset(0, -20).wait(0.1).move_by_offset(0, -20).wait(0.1).move_by_offset(0, -20).wait(0.1).move_by_offset(0, -20).wait(0.1).move_by_offset(0, -20).wait(0.1).move_by_offset(0, -20).wait(0.1).move_by_offset(0, -20).wait(0.1).move_by_offset(0, -20).release().perform()

# pause before scrolling up
time.sleep(3)
 
# Note: once perform is called, chain of commands is cleared.
#scroll up
action.press(thumbnails).move_by_offset(0, 20).wait(0.1).move_by_offset(0, 20).wait(0.1).move_by_offset(0, 20).wait(0.1).move_by_offset(0, 20).wait(0.1).move_by_offset(0, 20).wait(0.1).move_by_offset(0, 20).wait(0.1).move_by_offset(0, 20).wait(0.1).move_by_offset(0, 20).wait(0.1).move_by_offset(0, 20).wait(0.1).move_by_offset(0, 20).wait(0.1).move_by_offset(0, 20).wait(0.1).move_by_offset(0, 20).wait(0.1).move_by_offset(0, 20).release().perform()