Which image has the highest number of "white" class attributes?
"white" class attributes refers to ATT_CLASS = 'white'; highest number refers to max(count(ATT_CLASS_ID))
SELECT T1.IMG_ID AS IMGID FROM IMG_OBJ_att AS T1 INNER JOIN ATT_CLASSES AS T2 ON T1.ATT_CLASS_ID = T2.ATT_CLASS_ID WHERE T2.ATT_CLASS = 'white' GROUP BY T1.IMG_ID ORDER BY COUNT(T1.ATT_CLASS_ID) DESC LIMIT 1