Last modified: 2014-03-03 20:01:23 UTC
Steps to reproduce: 1. go to https://www.mediawiki.org/wiki/Multimedia/About_Media_Viewer 2. 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.
This was why we had #mediaviewer/File:Foobar.jpg/6 instead of just #mediaviewer/File:Foobar.jpg in the past - I made sure the index matched, so you got the same view no matter what. Though we could at least be cognisant of the order when opening the lightbox. Seems not difficult.
That scheme had other problems (not stable enough, not to mention ugly :) I would still go with #mediaviewer/<filename>/<index relative to other thumbnails of the same file>, with #mediaviewer/<filename>/1 being aliased to #mediaviewer/<filename>.
+1
