Responsive images in WordPress using srcset with Advanced Custom Fields Pro plugin

responsive-images-in-wordpress-with-advanced-custom-fields-pro.md

Responsive images in WordPress using srcset with Advanced Custom Fields Pro plugin

in functions.php:

add_filter( 'acf_the_content', 'wp_make_content_images_responsive' );

in template.php:

$image = get_field('my_image');
$img_src = wp_get_attachment_image_url( $image['id'], 'full' );											
$img_srcset = wp_get_attachment_image_srcset( $image['id'], 'full' ); ?>

<img src="<?php echo esc_url( $img_src ); ?>"
  width = "<?php echo $image['sizes']['Stripe-width']; ?>"
  height = "<?php echo $image['sizes']['Stripe-height']; ?>"
  srcset="<?php echo esc_attr( $img_srcset ); ?>"
  sizes="(max-width: 100vw) 480px" alt="<?php echo $image['alt']; ?>" />

Source: support.advancedcustomfields.com/forums/topic/wordpress-4-4-responsive-images/