Regardless of whether you use this CSS rule or not, it's a best practice to ALWAYS set the width and height attributes of any image. So even if you use this CS

Regardless of whether you use this CSS rule or not, it's a best practice to ALWAYS set the width and height attributes of any image. So even if you use this CSS rule, you should also set those width and height attributes. This allows the browsers to draw the correctly sized box whilst the image is still loading and whilst CSS hasn't kicked in yet.