You will probably have to break that big image up into tiles,
and keep vertical and horizontal offsets into an
array (grid) of them to decide which tile(s) to show.
You will encounter extra work to accommodate different size devices
if you want to sell your app.
You might be able to simulate dragging a Canvas by showing a
phalanx of image sprites on a low Z value for a background,
and sliding them in unison in a Sprite dragged event.
I have read that the Canvas can reach 3 times the
Screen size if you center it in the Screen.
I generally avoid images, and generate my own Canvas lines and text on the fly.
Maybe a more enthusiastic graphics fan can chime in here.
ABG