Kisekae Changer

Kisekae Changer was a service used for Japanese mobile phones, used to install various wallpapers.

Relation to the Metal Gear series
As part of a promotion for Metal Gear Solid 4: Guns of the Patriots, Kisekae Changer was tasked with releasing wallpapers depicting Old Snake and the four individual members of the Beauty and the Beast Unit. It was advertised as early as Tokyo Game Show 2008.