Don't you just love going to a page with plenty of info but everything's just crying out "look at me! Look at ME!!!"? Animated gifs have had plenty of practice at saying that. Not only that, there are so many that aren't convincing. Whoever created it was so busy trying to make the object move, that they didn't take into account the shape transitions of the actual object as it moved. Lost? I'll explain...
Take a bouncing ball for example. Now, if it isn't as hard as a rock, when it hits the ground, it will morph a little (squash up). One way to create convincing animations is to exaggerate this kind of thing so that it morphs a lot. This kind of thing is one of the things that makes a good animator. A good animator will be able to exaggerate all sorts of facial expressions of a character to bring it to life!
For the purposes of this article, we will stick to the good old bouncing ball scenario. If you look closely when it hits the ground, it reaches a pretty strong oval shape before bouncing back to its original shape.
It's a good thing to remember whenever you want a convincing 'cartoon style' animated gif.