Wagtail Picture Tag

Wagtail Picture Tag adds a picture template tag. This is not supposed to be a solution for all situations but to be a shortcut for most.

It accepts 3 main types of filters: formats, resizing methods and sizes.

Formats

By default it will try and create JPEG, PNG, WEBP and AVIF (if available).

You may use format-jpeg, format-png, format-webp, format-gif and format-avif

There are also two format shortcuts:

• photo - will create JPEG, WEBP and AVIF
• transparent - will create WEBP, PNG and AVIF

Resizing

Resizing methods are the same as Wagtails with the exception that you can provide multiple filters

Sizes

Sizes are automatically generated to match resizing filters provided but can be specified for more responsive sizes.

size-250px will create sizes="250px" size-max100-300vw size-250px will create sizes="(max-width: 300px) 100vw, 250px"

Lazy

It also takes the argument lazy that simply adds loading="lazy" to the HTML tag.

AVIF

Currently Willow (the image library used by Wagtail) does not support AVIF but support can be patched in by installing willowavif package.

Quick start

1. Install the package:

   pip install wagtail-picture-tag

2. Add "wagtail-picture-tag" to your INSTALLED_APPS setting like this:

   INSTALLED_APPS = [
       ...
       'wagtail_picture_tag',
   ]

3. Include the tag in your template:

   {% load picture_tags %}

4. Use the tag:

   {% picture image photo fill-640x480 fill-320x240 %}

AVIF support

All that is needed is to install the willowavif package, it is then automatically imported and used.

Testing

Testing is done with pytest. Install and test can be done with:

pip install -r requirements.txt -r requirements.dev.txt
pytest