Description

When using the lightbox behavior for the Image block that contains a dark image, it displays the Close button in a way that is hard to see it.

Step-by-step reproduction instructions

1. Activate the experiment that enables Interactivity API and Behaviors.
2. Go to the post editor.
3. Upload an image with a dark area around borders, for example:

4. Set the Resolution to Full Size. Alternatively, it might work with different settings depending on the screen-size used.
5. In the advanced settings for the Image block, activate the lightbox behavior.
6. Publish the post.
7. Navigate to the post on the front end.
8. Open the lightbox and check whether the Close button is correctly displayed.

Screenshots, screen recording, code snippet

Editor view:

Frontend view:

Lightbox view:

Environment info

• WordPress 6.2, Gutenberg latest (trunk)

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