A suggestion. Might be a good idea (or not, of course):
numpad keys 1-9 fast scroll to the edges/corners of the image.
workflow example:
you have a large image zoomed in
numpad 7 = scrolls to the upper left corner (of the image)
numpad 8 = scrolls to the top edge (of the image)
numpad 9 = scrolls to the upper right corner (of the image)
(...)
numpad 5 = scrolls to the center (of the image)
(...)
numpad 3 = scrolls to the bottom right (of the image)
Best regards
K