They should all be the same size

.. image:: images/biohazard.png
   :width: 64
   :scale: 100

.. image:: images/biohazard.png
   :width: 128
   :scale: 50

.. image:: images/biohazard.png
   :width: 256
   :scale: 25

They should be doubling in size, keeping aspect ratio

.. image:: images/biohazard.png
   :width: 16

.. image:: images/biohazard.png
   :width: 32

.. image:: images/biohazard.png
   :width: 64
