Rotated thin ImageMobjects jitter on animation

When an ImageMobject is much taller than wide, rotated, and then moved in an animation, it jitters around its supposed position.

```python
class TestScene(Scene):
def construct(self):
pencil = ImageMobject(filename_or_array='pencil_white2').rotate(TAU/8)
self.add(pencil)
self.play(pencil.move_to, RIGHT)
```

- This only happens with images that are taller than wide, not the other way around.
- The initial rotation is necessary to produce the bug.
- An unrotated ImageMobject also jitters on `self.play(pencil.rotate, TAU/4)`, but not on `self.play(Rotate(pencil, TAU/4))`.