The answer is no, currently all media data are non-localizable. There was several reasons for this but the main one was that we did not have time to manage all bugs/quirks that appear when you need to deal with localizable media. Therefore, the decition was to handle media as non-localizable content (just as the old VPP based file system), as least for the EPiServer 7.5 release.
Is it possible in 7.5 to specify culture specific properties for ImageData/MediaData classes? I tried below, but it doesn't seems to work: