Get the Wordpress attachment image url - php

Question

I am trying to display all the images attached to a wordpress post and link the image to the source of the image to open it in a light box. I am using the following code:
if (have_posts())
{
while (have_posts())
{
the_post();
$args = array(
'orderby' => 'title',
'order' => 'ASC',
'post_type' => 'attachment',
'numberposts' => -1,
'post_status' => null,
'post_parent' => $post->ID,
'exclude' => get_post_thumbnail_id()
);
$attachments = get_posts( $args );
if ($attachments)
{
foreach ($attachments as $attachment)
{
?>
<div id="image">
<a rel="lightbox" href="<?php /* ??? */ ?>">
<?php echo wp_get_attachment_image ($attachment->ID, 'full'); ?>
</a>
</div>
<?php
}
}
}
}
I have tried many things where the ??? but i can't seem to retrieve just the source url.
Can anyone provide some insight?

Answer 1

Use wp_get_attachment_image_src
https://codex.wordpress.org/Function_Reference/wp_get_attachment_image_src
This:
wp_get_attachment_image_src( $attachment->ID, 'full' );
should return an array with the following elements
[0] => url
[1] => width
[2] => height
[3] => boolean: true if $url is a resized image, false if it is the original or if no image is available.

Answer 2

If you just want to link to the original full image it's better to simply use "wp_get_attachment_url" - https://developer.wordpress.org/reference/functions/wp_get_attachment_url/
The wp_get_attachment_image_src function will run code you don't need and return extra details you don't need making your code less efficient.