What are the MPEG pictures that are coded with respect to the nearest previous I- or P-picture?

What are the MPEG pictures that are coded with respect to the nearest previous I- or P-picture?

These are called predicted pictures (P-pictures or P-frames). This technique is termed forward prediction. P-pictures provide more compression than I-pictures and serve as a reference for future P-pictures or B-pictures. P-pictures can propagate coding errors when P-pictures (or B-pictures) are predicted from prior P-pictures where the prediction is flawed.