The problem with using a picture of your significant other as your phone wallpaper is that it's awkward to ever change it away. Luckily my wife just changed her lock screen from a photo of me to a photo of a baby we like, so I'm changing mine to one of the cool maps offered by Alvar Carto.
Screenshot: Nick Douglas (Alvar Carto)
Alvar Carto, one of those outlets that sell trendy map posters, built a simple mobile-friendly site that will pop out a minimalist map of any location you enter, at the right resolution for most major phones.
If you want more options, make a free account at Mapbox (a more technical service built for developers) and go to their static API playground to customise a map in 17 different styles. Remember to check the "retina" box for a max resolution of 2560x2560, and go nuts:
Screenshot: Nick Douglas (Mapbox)
Phone Background [Alvar Carto]
Static API Playground (free account required) [Mapbox]