The distortion of both graphs is truncated distortion, but the top edges that will not be truncated are different. The waveforms of the two pictures are the same, but the types of transistors are different, so the causes of distortion are different.

The first picture is PNP type, truncated wave type, which belongs to cut-off distortion, because the waveform has reached the ground and can't come down. This is because the quiescent current of the transistor is set too small, or the value of the resistor RC is too small.

The second picture is NPN type, truncated wave type, which belongs to saturation imbalance, because the lowest voltage after transistor saturation is ground, and it can't be lower. This is because the static current setting of the transistor is too large, or the value of the resistor RC is too large.

Generally speaking, the best static state of a single-stage transistor is that the collector voltage is equal to half of the power supply voltage. If it is less than half, the bottom waveform is clipped; if it is more than half, the top waveform is clipped.