https://shoptennyson.com/wp-content/themes/listable-child/assets/public/inc/front-page-image-widget.js

1/**
2 * Admin front page image widget
3 * Derived from: https://hughlashbrooke.com/2015/12/18/create-a-custom-featured-image-box/
4 */
5function frontPageImageWidgetAdmin_media(parentSelector) {
6
7    var parent = jQuery(parentSelector),
8        button = parent.find('.frontPageImageWidgetAdmin_button'),
9        input = parent.find('.frontPageImageWidgetAdmin_input'),
10        image = parent.find('img');
11
12    if( button.hasClass('frontPageImageWidgetAdmin_button-add') ) {
13
14        // Create the media frame.
15        var file_frame = wp.media.frames.file_frame = wp.media({
16            title: 'Choose an image',
17            button: { text: 'Set image' },
18            multiple: false,
19        });
20
21        // When an image is selected, run a callback.
22        file_frame.on('select', function() {
23            var attachment = file_frame.state().get('selection').first().toJSON();
24
25            input.val(attachment.id);
26            image.attr('src',attachment.sizes.thumbnail.url).show();
27            button.text('Remove image')
28                .removeClass('frontPageImageWidgetAdmin_button-add')
29                .addClass('frontPageImageWidgetAdmin_button-remove');
30        });
31
32        // Open the modal.
33        file_frame.open();
34
35    } else {
36        input.val('');
37        image.hide();
38        button.text('Set image')
39            .removeClass('frontPageImageWidgetAdmin_button-remove')
40            .addClass('frontPageImageWidgetAdmin_button-add');
41    }
42}