Template tags that generate tiny blurry placeholder images alongside your wagtail images in order to lazy-load them medium.com style.

Install using pip: pip install wagtail-lazyimages

1. Add wagtail_lazyimages to your INSTALLED_APPS setting like this:

   INSTALLED_APPS = [
       ...
       'wagtail_lazyimages',
   ]
   

2. Load the lazyimages_tags template tag library in your template:

   {% load "lazyimages_tags" %}
   

3. Replace wagtail's image tag with lazy_image for images that should lazy load:

   {% lazy_image page.photo width-960 class="lazy" %}
   

   This template tag behaves just like wagtail's image tag with the exception that it generates an additional scaled down and blurred placeholder image. The URL of the placeholder image will appear in the src attribute of the image tag while the large version will be referenced in data-src:

   <img src="/path/to/placeholder-image.jpg" data-src"/path/to/image.jpg" class="lazy" />
   

4. In the front end: Implement the lazy loading functionality yourself or use a dedicated JavaScript library like lozad.js:

   const observer = lozad('.lazy');
   observer.observe();
   

If you want to use a different attribute for referencing the original image than data-src use the parameter lazy_attr for that:

{% lazy_image page.photo width-960 lazy_attr="data-lazy-url" class="lazy" %}

If you need to assign the image data to a template variable using Django's as syntax, the URL of the placeholder image is stored in the lazy_url attribute:

{% load "lazyimages_tags" %}

{% lazy_image page.photo width-960 as img %}

<img data-src="{{ img.url }}" src="{{ img.lazy_url }}" width="{{ img.width }}"
     height="{{ img.height }}" alt="{{ img.alt }}" />

In case you need to use Wagtail's attrs shortcut use lazy_attrs instead:

{% load "lazyimages_tags" %}

{% lazy_image page.photo width-960 as img %}

<img {{ img.lazy_attrs }} class="custom-class" />