There is nothing in the theme (or any theme, really) that ever touches content (other than the HTML insertion areas, which are essentially unique to Weaver).
It is extremely unlikely that anything in updated versions of Weaver Xtreme would do anything to NextGen anything.
There is nothing revealed in the link you provided.
But, really, Weaver never directly fiddles with posts or pages or media files, or entries in the WordPress database other than its own settings.