Please list the IDs of all the images with more than 2 pairs of object samples with the relation "parked on".
IDs of all the images refers to IMG_ID; relation "parked on" refers to PRED_CLASS = 'parked on'; more than 2 pairs refers to count(IMG_ID) where OBJ1_SAMPLE_ID ! = OBJ2_SAMPLE_ID
SELECT T2.IMG_ID FROM PRED_CLASSES AS T1 INNER JOIN IMG_REL AS T2 ON T1.PRED_CLASS_ID = T2.PRED_CLASS_ID WHERE T1.PRED_CLASS = 'parked on' AND T2.OBJ1_SAMPLE_ID != T2.OBJ2_SAMPLE_ID GROUP BY T2.IMG_ID HAVING COUNT(T2.IMG_ID) > 2