Предварительная нарезка и сжатие изображений с сохранением путей в json.

preparse srcset

{% spaceless %}

{% set srcsets = [] %}
{% for image in entry.images %}    

    {% set imgSize = max(image.width, image.height) %}
    {% set transformedImages = craft.imager.transformImage(image, [
	    { width: imgSize >= 1200 ? 1200 : imgSize, jpegQuality: 90 }, 
	    { width: imgSize >= 1000 ? 1000 : imgSize, jpegQuality: 90 }, 
	    { width: 600 }, 
	    { width: 300, jpegQuality: 65 }, 
	    { width: 100, jpegQuality: 65 }
	    ], {
        format: 'jpg', 
        ratio: 1/1, 
        position: 'center-center', 
        mode: 'letterbox',
        auto: 'format,compress'	    
	}) %}	

    {% set arr = {
        maxSize: imgSize,
    	w1200: transformedImages[0].url,
    	w1000: transformedImages[1].url,
    	w600: transformedImages[2].url,
    	w300: transformedImages[3].url,
    	w100: transformedImages[4].url       
    } %}

    {% set srcsets = srcsets|merge([arr]) %}

{% endfor %}
{{ srcsets|json_encode() }}

{% endspaceless %}