Output custom image before value with WP Job Manager Field Editor

functions.php

<?php
// ^ there should only be one of these at the top of your child theme's functions.php file

// Filter below means the META KEY for the field is "job_staff_gender"
// Syntax for filter is field_editor_output_as_value_METAKEY (replacing METAKEY with the actual meta key)
add_filter( 'field_editor_output_as_value_job_staff_gender', 'smyles_job_staff_output_gender_image', 10, 4 );

function smyles_job_staff_output_gender_image( $field_value, $meta_key, $listing_id, $args ) {

	switch ( $field_value ) {
		// The value here MUST match the value from field EXACTLY
		case 'male':
			$img = 'male.png';
			break;

		case 'female':
			$img = 'female.png';
			break;

		default:
			// If none of case above match, set false to prevent outputting image (since we can't match it to one)
			$img = false;
			break;
	}

	// Only prepend HTML image markup if $img is set from above
	if( ! empty( $img ) ){
		// This assumes you have "male.png" or "female.png" file in /images/ directory inside your child theme
		// or whatever image file you define above
		$image_url = get_stylesheet_directory_uri() . '/images/' . $img;
		// Prepend the field value returned with image HTML markup
		$field_value = "<img src='" . $image_url . "' class='some-image-class'>" . $field_value;
	}

	return $field_value;
}