Width and height can be styled for images as well as having width and height attributes.

width: <length> | <percentage> | auto 
height: <length> | auto

• Width and height can be specified for block-level elements and images
• One can be specified as auto in which case aspect ratio is maintained

<p><img style="width:170px  ; height:auto" src="../pngs/microscope.png" 
  alt="Microscope"/>
<img style="width:auto  ; height:215px" src="../pngs/microscope.png" 
  alt="Microscope"/></p>