Check the right object's height in qCompare for QImage and QPixmap.

Fixes http://www.viva64.com/en/b/0251/, Typo No. 3 and 4

Change-Id: Icbd33534dbf424e00e4c351ae5ee0e3daa99e7b9
Reviewed-by: Jørgen Lind <jorgen.lind@digia.com>