Map facet – dynamic icon based on an ACF field

<?php
// for image field set to return object
add_filter( 'facetwp_map_marker_args', function( $args, $post_id ) {
    $field = get_field( 'image_field_name', $post_id ); // Get this post's ACF value
    $args['icon'] = $field['url'];
    return $args;
}, 10, 2 );

// for image field set to return url
add_filter( 'facetwp_map_marker_args', function( $args, $post_id ) {
    $field = get_field( 'image_field_name', $post_id ); // Get this post's ACF value
    $args['icon'] = $field;
    return $args;
}, 10, 2 );

// for image field set to return image id
add_filter( 'facetwp_map_marker_args', function( $args, $post_id ) {
    $field = get_field( 'image_field_name', $post_id ); // Get this post's ACF value
    $args['icon'] = wp_get_attachment_image_src( $field ); // see wp_get_attachment_image_src for specifiying size and/or other attributes
    return $args;
}, 10, 2 );