Easy way to have text linking to images

functions.php

<?php

add_filter( 'attachment_fields_to_edit', 'km_attachment_text_link_field', 10, 2 );

function km_attachment_text_link_field( $form_fields, $post ) {
	$form_fields['km-text-link'] = array(
		'label' => 'Text Link',
		'input' => 'text',
		'value' => '',
		'helps' => 'If Text Link is provided, the image will be linked from a text link',
	);

	return $form_fields;
}


add_filter( 'attachment_fields_to_save', 'km_attachment_field_save', 10, 2 );

function km_attachment_field_save( $post, $attachment ) {
	if ( isset( $attachment['km-text-link'] ) ) {
		update_post_meta( $post['ID'], 'km-text-link', $attachment['km-text-link'] );
	} else {
		delete_post_meta( $post['ID'], 'km-text-link' );
	}

	return $post;
}


add_filter( 'image_send_to_editor', 'km_image_text_links_format', 10, 8 );

function km_image_text_links_format( $html, $id, $caption, $title, $align, $url, $size, $alt ) {
	$text = get_post_meta( $id, 'km-text-link', true );

	if ( !empty( $text ) ) {
		list( $img_src, $width, $height ) = image_downsize( $id, $size );
		$html = '<a href="' . esc_url( $img_src ) . "\">$text</a>";
	}

	delete_post_meta( $id, 'km-text-link' );

	return $html;
}