I want to show post's uploaded images but it doesn't show... What am I doing wrong?

        $gallery            = array();
        if ( function_exists('fw_get_db_post_option') ) {
        $gallery        = fw_get_db_post_option( $post->ID, 'gallery', true );
         }                    
        if( !empty( $gallery ) ) { ?>
        <div class="tg-innerbannerholder">
            <div id="tg-innerbannerslider" class="tg-innerbannerslider tg-ad-gallery owl-carousel" data-pswp-uid="1">
            <?php 
                foreach( $gallery as $key => $value ) {
                    $thumb  = listingo_prepare_image_source($value['attachment_id'],480,380);
                ?> 
                <figure class="item" itemprop="associatedMedia" itemscope itemtype=""> 
                    <a class="spv-ag-gallery" href="<?php echo esc_url( $value['url'] ); ?>" data-rel="prettyPhoto[gallery]">
                        <img src="<?php echo esc_url( $thumb ); ?>" alt="<?php echo esc_attr( get_the_title( $value['attachment_id'] ) ); ?>">
                     </a>
                </figure>                       
            <?php } ?>
            </div>
            <?php
            $script = "
            jQuery(document).ready(function(){
                jQuery('#tg-innerbannerslider').owlCarousel({
                    items:4,
                    nav:false,
                    margin:0,
                    loop:true,
                    dots:false,
                    center: true,
                    autoplay:false,
                    rtl: ".listingo_owl_rtl_check().",
                    smartSpeed:450,
                    responsive:{
                            0:{items:1,},
                            992:{items:2,},
                            1200:{items:4,}
                        },
                    navClass: ['tg-btnprev', 'tg-btnnext'],
                    navContainerClass: 'tg-innerbannerbtns',
                    navText: [
                            '<span><i class=\"lnr lnr-chevron-left\"></i></span>',
                            '<span><i class=\"lnr lnr-chevron-right\"></i></span>',
                        ],
                });
            });";

            wp_add_inline_script('listingo_callbacks', $script, 'after');
            ?>
        </div>
    <?php } ?>