<a href="{{ book.get_absolute_url }}">
<img src="{{ book.cover_thumb.url }}" alt="{{ book.pretty_title }}" title="{{ book.pretty_title }}">
</a>
<a href="{{ book.get_absolute_url }}">
<img src="{{ book.cover_thumb.url }}" alt="{{ book.pretty_title }}" title="{{ book.pretty_title }}">
</a>