[justsomehnguy]

You missed the forest:

>> A circle can be rotated in place. It doesn’t take more space than the initial circle. *A square cannot.*

Edit: and just in case you or someone else miss the forest again:

the site developer treats the image as a circle, assuming rotating the image would change only the image.

[Izkata]

And it does only change the image, because it's a CSS animation. For page rendering purposes, browsers only use the size and position of the un-rotated image. It's even visible in the Grumpy Cat example, the rotated image overlaps the edges of the table because CSS transformations don't affect the rest of the page.