How to integrate Cloudinary into Headline's feature images

Themes
1

I am using the Headline theme but have a problem with the feature image served from Cloudinary (previously, I am successfully integrated Cloudinary with Ghost) post images have been served from Cloudinary but not the feature image, it shown as a broken image icon instead of a feature image.

Here the code of feature image used by Headline theme:

{{#if feature_image}}
    <figure class="gh-article-image">
            <img 
                srcset="{{img_url feature_image size="s"}} 300w,
                    {{img_url feature_image size="m"}} 720w,
                    {{img_url feature_image size="l"}} 960w,
                    {{img_url feature_image size="xl"}} 1200w,
                    {{img_url feature_image size="xxl"}} 2000w"
                sizes="(max-width: 1200px) 100vw, 1200px"
                src="{{img_url absolute="true" size="xl"}}"
                alt="{{title}}"
            >
        {{#if feature_image_caption}}
            <figcaption>{{feature_image_caption}}</figcaption>
        {{/if}}
    </figure>
{{/if}}

Please help…