When there are more than 24 pictures in a second, people's naked eyes will look like continuous images. So when making an animation, there will be 24 paintings in one second, usually one is called a frame or a grid, which is called "コマ" in Japanese.
Disney's animation has 24 pictures in 1 second, and each picture is drawn. The effect is quite good, but the workload is quite large. In Japan, 24 frames per second is called full-frame animation, which can be translated into "full-frame animation". The earliest Nissan animated films were all like this, learning from Europe and America. But the cost is too high and it can only be made into a movie. So the Lion King 2 you saw is probably made in this way. But I'm just an amateur, and the specific production process is not very clear, but I can get a general understanding.