Fix image embedding in URL previews and add image viewer

[skidoodle]

Description

This PR improves how URL previews render images and adds the ability to view them.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings

[Sollace]

Does this have overlap with #2309 ?

[skidoodle]

yes