For a display position, the user specifies {HEAD ~ at least one subregion} of {TAIL ~ the subdivided original image} 
of
For a display position , the user specifies { HEAD ~ at least one subregion } of { TAIL ~ the subdivided original image }
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL