Those screenshots were from Kiara the Brave. The movie is also called by the name Super K. The creators have uploaded it on youtube if you want to see it.
Mockbusters and ripoffs have the worst animation I've ever seen. Ugly CGI models or lazy Flash tweening, like with Video Brinquedo movies. Dingo Pictures films are barely even animated.
Delgo, Foodfight and Sir Billi are probably the worst animations where the creators actually had ambition and tried hard to make something worthwhile, but failed.
Out of 2D animations, I have particular dislike for Secret of NIMH 2 and Balto 2. They've got a pretty bad drop in quality compared to the first movie.
This Tom & Jerry movie seems to have some weird faces that have quickly become popular reaction images, but I don't think the art looks bad enough to qualify as all-time worst animation.