ACF & WordPress Media Library

I’ve got an ACF ‘options page’ with a placeholder image within, to fall back to if a client removes the image from the post/page by mistake. And I’m using the following code to handle this situation happening.

<?php
// Variables
$banner_image = get_field('banner_image');   
$fallback_banner_image = get_field('fallback_image', 'options');
?>

<?php if ( $banner_image ): { ?>

<img class="hero-content" src="<?php echo esc_url( $banner_image_src[0] ); ?>" srcset="<?php echo esc_attr( $banner_image_srcset ); ?>" sizes="100vw" alt="<?php echo $banner_image_alt_text ?>">

<?php } elseif ( empty( $banner_image ) ): { ?>
   
<img class="hero-content" src="<?php echo esc_url( $fallback_banner_image_src[0] ); ?>" srcset="<?php echo esc_attr( $fallback_banner_image_srcset ); ?>" sizes="100vw" alt="<?php echo $fallback_banner_image_alt_text ?>">

<?php } endif; ?>

This works fine once pages or posts are saved.

However

The issue I have is if the page/post has been previously saved with an image and then a user deletes the image from the Media Library directly, the field doesnt become ’empty’ so the content just disappears, rather than falling back to the placeholder image that I would like it to.

Any advice on how to handle images directly removed from the Media Library?

Thanks.