Image restrictions

Some animations draw their effect with a ::before or ::after pseudo-element — and a plain <img> tag can't host one; browsers never render pseudo-elements on replaced elements like images, videos or form inputs. Border is the only entrance/hover animation that needs one, so it's the only one this applies to.

To use Border on an image, wrap the image in a container (a <div>, a Bricks/Etch container block, or a block editor Group block) and put the animation class on that wrapper instead of on the image itself.

The Border animation goes on the wrapper (the Div), not on the image inside it.