1. Add jekyll_picture_tag to your Gemfile in the :jekyll_plugins group.


    It’s NOT jekyll-picture-tag.

     # Gemfile
     gem 'jekyll', '~> 4.0'
     group :jekyll_plugins do
       # (other jekyll plugins)
       gem 'jekyll_picture_tag', '~> 2.0'
  2. Run $ bundle install
  3. Install libvips. Most package managers know about it, otherwise it can be found here.
  4. Install libvips dependencies for all image formats you will use, such as libpng, libwebp, libjpeg, and libheif (for avif). Note that if you use a deployment or CI service, these dependencies will be required there as well.
  5. Optional: Install ImageMagick for additional image formats. If vips runs into an image format it can't handle (jp2 on my particular installation), JPT will instruct it to try ImageMagick instead.