I tried to include a translated version of an image file (svg) with language attribute, for example,
[[File:Gerrit patchset 25838 test.svg|lang=ne]] [[File:Gerrit patchset 25838 test.svg|lang=fr]]
This does not show translated version of svg file in preview mode. But displays translated version after saving. What is the reason behind this?
At a guess, Parsoid probably doesn't support this feature yet, at least in your web browser.
Yes, most likely T208620. It's not too hard to fix, but we're in a code freeze at the moment. T60920 would be in effect if we were shipping the raw SVG to the browser, but I expect that preview mode is still Doing The Right Thing and sending a thumbnail -- we're just not passing the right options when we get the thumbnail (yet).