• add to INSTALLED_APPS

• configure:

• LAZYTHUMBS_404_CACHE_TIMEOUT how long before a 404'd thumbnail request is retried

• LAZYTHUMBS_CACHE_TIMEOUT how long before a thumbnail gets regenerated

• LAZYTHUMBS_DUMMY whether or not the lazythumb template tag just uses placekitten

• LAZYTHUMBS_URL url prefix for lazythumb requests. used by template tag. (usually MEDIA_URL or '')

• add to urls.py

    (r'^lt/', include('lazythumbs.urls'))
  

• ask for a tiny kitten

    mysite.com/lt/lt_cache/thumbnail/20x20/kitten.jpg/
  

• use in a template

    {% load lazythumb %}
    {% lazythumb img_file scale '80x80' as img %}
        <img {% img_attrs img %} alt="{{img_file.name}}" />
    {% endlazythumb %}
    {% lazythumb img_file resize '80x60' as img %}
        <img {% img_attrs img %} alt="{{img_file.name}}" />
    {% endlazythumb %}
    {% lazythumb img_file thumbnail '80' as img %}
        <img {% img_attrs img %} alt="{{img_file.name}}" />
    {% endlazythumb %}
  

• delay the size until the layout is known, for responsive designs

    <script type="text/javascript" src="{{ STATIC_URL }}lib/lazythumbs/js/lazythumbs.js"></script>
  
    {% lazythumb img_file thumbnail 'responsive' as img %}
        <img {% img_attrs img %} alt="{{img_file.name}}" />
    {% endlazythumb %}
  

lazythumbs acts as a PIL proxy for images stored in MEDIA_ROOT. It looks for the requested image and, if found, generates a new image and writes it to the filesystem at MEDIA_ROOT/lt_cache. If the request resulted in a 404 this is recorded in cache to avoid getting hammered by repeated requests for images that don't exist.

• scale scale image to desired dimensions (no attention paid to ratio)
• thumbnail scale in a single dimension (eg "80" or "x48")
• resize thumbnail then center crop to desired dimensions

as its first argument the template tag accepts either a string or an object (and Variables pointing to either). If the argument is an object (say, an ImageFile) lazythumbs will introspect and hunt for width, height, and path properties at various levels under various names. This lets us compute ahead of time the intended width/height of the new image and provide it to the template context. This is nice: you can speed up page rendering by having your img tags use preset dimensions but you won't have to take the time to actually compute and save the new image at template render time. Django's ImageFile will hit the filesystem to get dimensions but caches them in memory: you'll only have to pay that cost once in your process.

lazythumbs is in many ways a combination of sorl-thumbnail and thumpy and owes its existence to them both.

lazythumbs was written by nathaniel k smith nathanielksmith@gmail.com for cmg digital&strategy and is licensed under the terms of the MIT license.