The simple way is to add a group around the image. Set the group content overflow to hidden thus using the group as a mask.
When you drag the map within you should not be able to drag it out of bounds.
map.hype.zip (496.1 KB)
Also an example of tile type dragging with animation can be found here.
Adapted example.
map drag tiles.hype.zip (522.6 KB)
( Take note of the bit about removing the returns to get diagonal type Drag)