The behaviour is even stranger than I thought. Used unadorned, \XeTeXpicfile introduces a significant right shift for all text that follows it on the current page; concealed within a \centerline, all is well yet concealed within braces the artifact remains (so it is not a scoping issue).
"Curiouser and curiouser", said Alice. ** Phil. -------------------------------------------------- Subscriptions, Archive, and List information, etc.: http://tug.org/mailman/listinfo/xetex
