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+++ b/README.md
@@ -2592,6 +2592,7 @@ img.convert(mode='RGB').save('test.png')
 ### Animation
 #### Creates a GIF of a bouncing ball:
 ```python
+# $ pip3 install imageio
 from PIL import Image, ImageDraw
 import imageio
 HEIGHT, R = 126, 10
diff --git a/index.html b/index.html
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@@ -2203,7 +2203,8 @@ img.convert(mode=<span class="hljs-string">'RGB'</span>).save(<span class="hljs-
 <li><strong><code class="python hljs"><span class="hljs-string">'RGB'</span></code> - 3x8-bit pixels, true color.</strong></li>
 <li><strong><code class="python hljs"><span class="hljs-string">'RGBA'</span></code> - 4x8-bit pixels, true color with transparency mask.</strong></li>
 <li><strong><code class="python hljs"><span class="hljs-string">'HSV'</span></code> - 3x8-bit pixels, Hue, Saturation, Value color space.</strong></li>
-</ul><div><h3 id="animation">Animation</h3><div><h4 id="createsagifofabouncingball">Creates a GIF of a bouncing ball:</h4><pre><code class="python language-python hljs"><span class="hljs-keyword">from</span> PIL <span class="hljs-keyword">import</span> Image, ImageDraw
+</ul><div><h3 id="animation">Animation</h3><div><h4 id="createsagifofabouncingball">Creates a GIF of a bouncing ball:</h4><pre><code class="python language-python hljs"><span class="hljs-comment"># $ pip3 install imageio</span>
+<span class="hljs-keyword">from</span> PIL <span class="hljs-keyword">import</span> Image, ImageDraw
 <span class="hljs-keyword">import</span> imageio
 HEIGHT, R = <span class="hljs-number">126</span>, <span class="hljs-number">10</span>
 frames = []