If 31
<<969>>[<<969>><<970>>urx,ury<<970>><<971>>]<<971>> is present, then it should specify the coordinates
of the top right corner of the image, as a pair of TEX dimensions.
If the units are omitted they default to |bp|. So |[1in,1in]| and
|[72,72]| are equivalent. If only one optional argument appears, the
lower left corner of the image is assumed to be at |[0,0]|. Otherwise
31
<<975>>[<<975>><<976>>llx,lly<<976>><<977>>]<<977>> may be used to specify the coordinates of this point.