This bug is related to how the magic words are evaluated when a commons page is being viewed with either a uselang set, or more importantly, when it is being viewed on another language project.
None of the date and time magic words given at http://www.mediawiki.org/wiki/Help:Magic_Words#Date_and_time localize when viewed at a project with a different language. Neither does {{formatnum}} or using {{#expr:}}. Note that I haven't tried other magic words returning digits, but I suspect that their digits don't localize either.
Tests were done using http://commons.wikimedia.org/wiki/File:Compass_rose-hi.svg and viewing it via different language projects and specifying uselang for it.(look through the history if there's no magic word usage on it now).
Also note that simply specifying the language may not be enough since various languages (most indic languages atleast) use different numerals than the default for the language (i.e the standard arabic numerals 1,2,3...)
So, the usage of numerals should be the one which the local project is using, not the language default. I'm not asking for language specific number formatting here, just the numerals used.
Also, the monthnames, daynames etc should be used per the project's language, not the default(english).
Lastly, I know this may look/sound like a catch-all bug, but I'm just reporting this for now; split it if you have to.
Version: unspecified
Severity: enhancement