Significantly, Mgr. Gänswein did not celebrate at the "people's altar", but at the original high altar, ad orientem, and in Latin. You can see this in this video clip (in German, no embedding possible), but only second hand from a video screen to which the Mass was transmitted live, since the church was too small for all the 1100 people who attended, and photography was not allowed inside the church itself. Here is a photograph as well:
(see picture galleries of the occasion here and here).
Update 26/8/2009: The video has now been captured by gloria.tv:
Attendants of the celebration included, besides the Monsignor's family (here he is with his mother)
the Cardinal Archbishop of Madrid as well as Mgr. Wilhelm Imkamp, Consultor to the Congregation for Divine Worship and rector of the pilgrimage church of Maria Vesperbild which has been repeatedly mentioned on the NLM (see e.g. last year's post about the Assumption in Maria Vesperbild with Archbishop Ranjith). Mgr. Imkamp preached at Mgr. Gänswein's ordination 25 years ago.
Speaking of Maria Vesperbild, this year's Assumption Mass was celebrated by the new Archbishop of Munich and Freising (in which see he is succesor to Pope Benedict), Most Rev. Reinhard Marx. As is customary at Maria Vesperbild, Archbishop Marx celebrated ad orientem, and in full pontifical vestments. The Augsburger Allgemeine has an image gallery, as does our friend Martin Bürger of exsultet.net. Here is a sample:
There also is full video available from katholisch.tv.
Images of Mgr. Gänswein's jubilee by Südkurier/Badische Zeitung.