Add link upload image when URL is empty

Hi,
yours is a great plugin. But I wanted to tell you that it does not give the possibility to upload the image, if the variable $ thumb_url is empty despite WP signals true with has_post_thumbnail. This happens when, for example, you import a post with attachments and cannot find the attachment.
There is a way to add the button:

Nel file featured-image-admin-thumb-fiat/admin/class-featured-image-admin-thumb-admin.php si potrebbe fare la seguente modifica:

public function fiat_custom_columns( $column, $post_id ) {
		switch ( $column ) {
			case 'thumb':
				if ( has_post_thumbnail( $post_id ) ) {
					// Determine if our image size has been created and use
					// that size/attribute combination
					// else get the post-thumbnail image and apply custom sizing to
					// size it to fit in the admin dashboard
					$sizes        = '';
					$thumbnail_id = get_post_thumbnail_id( $post_id );
					$tpm          = wp_get_attachment_metadata( $thumbnail_id );
					if ( false !== $tpm && ! empty( $tpm ) ) {
						$sizes = $tpm['sizes'];
					}

					// Default to thumbnail size (as this will be sized down reducing the bandwidth until the image thumbnail is regenerated)
					$fiat_image_size = 'thumbnail';

					// Review the sizes this particular image has been set to
					if ( is_array( $sizes ) ) {
						foreach ( $sizes as $s => $k ) {
							if ( $this->fiat_image_size === $s ) {
								// our size is present, set it and break out
								$fiat_image_size = $this->fiat_image_size;
								break;
							}
						}
					}
					/**
					 * Check if WooCommerce is active
					 * If so, only return anchor link markup to inline edit thumbnail
					 * WooCommerce will supply the image markup
					 **/
					if ( $this->fiat_on_woocommerce_products_list() ) {
						$thumb_url = '';
					} else {
						if ( 'thumbnail' === $fiat_image_size ) {
							// size down this time
							$thumb_url = wp_get_attachment_image( $thumbnail_id, array( 60, 60 ) );
						} else {
							// use native sized image
							$thumb_url = get_image_tag( $thumbnail_id, '', '', '', $fiat_image_size );
						}
					}
					// Here it is!
					$this->fiat_nonce = wp_create_nonce( 'set_post_thumbnail-' . $post_id );
					
					if( $thumb_url === '' ) {
						
						$this->fiat_nonce   = wp_create_nonce( 'set_post_thumbnail-' . $post_id );
						$set_featured_image = sprintf( __( 'Set %s featured image', 'featured-image-admin-thumb-fiat' ), '<br/>' );
						$set_edit_markup    = $this->fiat_on_woocommerce_products_list() ? '' : $set_featured_image;

						$html = sprintf(
							$this->template_html,
							admin_url( 'media-upload.php?post_id=' . $post_id . '&type=image&TB_iframe=1&_wpnonce=' . $this->fiat_nonce ),
							$set_edit_markup,
							$post_id
						);
						
						// Click me!
						echo wp_kses( $html, $this->fiat_kses );
						
					} else {

						$html = sprintf(
							$this->template_html,
							admin_url( 'media-upload.php?post_id=' . $post_id . '&type=image&TB_iframe=1&_wpnonce=' . $this->fiat_nonce ),
							$thumb_url,
							$thumbnail_id
						);

						// Click me to change!
						echo wp_kses( $html, $this->fiat_kses );
						
					}
				} else {

					$this->fiat_nonce   = wp_create_nonce( 'set_post_thumbnail-' . $post_id );
					$set_featured_image = sprintf( __( 'Set %s featured image', 'featured-image-admin-thumb-fiat' ), '<br/>' );
					$set_edit_markup    = $this->fiat_on_woocommerce_products_list() ? '' : $set_featured_image;

					$html = sprintf(
						$this->template_html,
						admin_url( 'media-upload.php?post_id=' . $post_id . '&type=image&TB_iframe=1&_wpnonce=' . $this->fiat_nonce ),
						$set_edit_markup,
						$post_id
					);
					// Click me!
					echo wp_kses( $html, $this->fiat_kses );
				}
				break;
		}
	}

I extended the class to make the change.
But it would clearly be appropriate to make the change natively. 🙂