Update documentation

Author: AllenDowney

_sources/index.md

@@ -5,8 +5,7 @@ You can order print and ebook versions of the third edition from
 [Bookshop.org](https://bookshop.org/a/98697/9781098155438) and
 [Amazon](https://www.amazon.com/_/dp/1098155432?smid=ATVPDKIKX0DER&_encoding=UTF8&tag=oreilly20-20&_encoding=UTF8&tag=greenteapre01-20&linkCode=ur2&linkId=e2a529f94920295d27ec8a06e757dc7c&camp=1789&creative=9325).
 
-<img width="200" src="https://raw.githubusercontent.com/AllenDowney/ThinkPython/v3/think_python_3e.jpg" style="float: right; margin-left: 10px;">
-<br>
+<img width="250" src="https://raw.githubusercontent.com/AllenDowney/ThinkPython/v3/think_python_3e.jpg" style="float: right; margin-left: 10px;">
 
  [Here is the landing page for the book at Green Tea Press](https://greenteapress.com/wp/think-python-3rd-edition/).
 

index.html

@@ -383,8 +383,7 @@ <h1>Think Python<a class="headerlink" href="#think-python" title="Link to this h
 You can order print and ebook versions of the third edition from
 <a class="reference external" href="https://bookshop.org/a/98697/9781098155438">Bookshop.org</a> and
 <a class="reference external" href="https://www.amazon.com/_/dp/1098155432?smid=ATVPDKIKX0DER&amp;amp;_encoding=UTF8&amp;amp;tag=oreilly20-20&amp;amp;_encoding=UTF8&amp;amp;tag=greenteapre01-20&amp;amp;linkCode=ur2&amp;amp;linkId=e2a529f94920295d27ec8a06e757dc7c&amp;amp;camp=1789&amp;amp;creative=9325">Amazon</a>.</p>
-<img width="200" src="https://raw.githubusercontent.com/AllenDowney/ThinkPython/v3/think_python_3e.jpg" style="float: right; margin-left: 10px;">
-<br>
+<a class="reference internal image-reference" href="https://raw.githubusercontent.com/AllenDowney/ThinkPython/v3/think_python_3e.jpg"><img alt="https://raw.githubusercontent.com/AllenDowney/ThinkPython/v3/think_python_3e.jpg" src="https://raw.githubusercontent.com/AllenDowney/ThinkPython/v3/think_python_3e.jpg" style="width: 250px;" /></a>
 <p><a class="reference external" href="https://greenteapress.com/wp/think-python-3rd-edition/">Here is the landing page for the book at Green Tea Press</a>.</p>
 <p>For the third edition, the biggest changes are:</p>
 <ul class="simple">