Steps to reproduce:
- go to https://www.mediawiki.org/wiki/Multimedia/About_Media_Viewer
- Click on the first image of the How does Media Viewer work? section.
Observe that the caption is missing.
MediaViewer actually opened the first instance of the same image (somewhat higher on the page, has no caption), but this is not obvious and can be quite confusing when the caption has important information (e.g. legend for a chart is often placed there) and the user is expecting it.