```html <img class="nes-avatar is-large" src="https://www.gravatar.com/avatar?s=15" alt="Gravatar image example" style="image-rendering: pixelated;"> ```

```html <img class="nes-avatar is-large" src="https://www.gravatar.com/avatar" alt="Gravatar image example" style="image-rendering: pixelated;"> ```

没有 `?s=15` 就无法让 `image-rendering: pixelated;` 发挥作用。为什么？