Accessibility: Caption for horizontal row widget not associated with the image

[caaster]

Issue Description - WCAG standard

See the markup for the image on this exhibit page: https://exhibits.stanford.edu/stanford-aapi/feature/timeline, which shows that the caption is NOT associated with the image. This is incorrect for accessibility.

Method of discovery

Stanford Office of Digital Accessibility review of Exhibits, Stanford's Spotlight instance.

Steps to Reproduce

Create content on a home, feature, or about page using the horizontal row widget. Make sure to create a caption.

We should also check all of the widgets that allow captions to see if the same problem is present.

Suggested solution