:</p>

<pre class="p-3 mb-2 text-body-secondary bg-body-tertiary cli"><samp>magick -size 70x70 canvas: \
  -fx "Xi=i-w/2; Yj=j-h/2; 1.2*(0.5-hypot(Xi,Yj)/70.0)+0.5" \
  radial-gradient.png
</samp></pre>

<p>The command above returns this image:</p>

<ul>
  <a href="../images/radial-gradient.png"><img src="../images/radial-gradient.png" width="70" height="70" alt="radial-gradient" /></a>
</ul>

<p>This FX expression adds random noise to an image:</p>

<pre class="p-3 mb-2 text-body-secondary bg-body-tertiary