I'm trying to apply custom data-src and srcset attributes to images added in Customiser. The page is static with no loop and I have so far hard coded the data-src attribute with <?php echo wp_get_attachment_url( get_theme_mod( 'hero_img' ) ); ?> so it will take the url of the image selected by the user.
I presume adding srcset and sizes attributes could be done similarly, however I can't figure out how to unset the src attribute so that I can populate this using the value of data-src instead (for lazy loading). I've searched everywhere for an answer but all the solutions to similar problems involve the_content() or filters I don't have access to without a loop.
Surely there has to be an easier way to get responsive images and custom attributes working with a static site that has customiser fields to change media?
Any help would be massively appreciated, I'm probably going about this all wrong.
Many Thanks
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