Image: Lightbox doesn't work on image inserted from URL

[ajlende]

Description

Getting PHP errors when using the lightbox with images not in the media library.

( ! ) Notice: Undefined index: id in ./gutenberg/build/block-library/blocks/image.php on line 81

This happens in both the post editor and the frontend.

Step-by-step reproduction instructions

1. Add an image block
2. Use 'Insert from URL' to add an image
3. See PHP error

Or use the image block below.

<!-- wp:image {"sizeSlug":"large","behaviors":{"lightbox":true}} -->
<figure class="wp-block-image size-large"><img src="https://wp20.wordpress.net/wp-content/themes/twentyseventeen-wp20/images/wp20-logo-white.svg" alt="WP20 logo"/></figure>
<!-- /wp:image -->

Screenshots, screen recording, code snippet

No response

Environment info

No response

Please confirm that you have searched existing issues in the repo.

Yes

Please confirm that you have tested with all plugins deactivated except Gutenberg.

Yes

[SantosGuillamot]

I started this pull request to solve it. Thanks a lot for the report 🙂