Determines how the image set by wallpaper_filename is rendered. Possible values are "none", "wallpaper", "centered", "scaled", "stretched", "zoom", "spanned".
Penodi sut mae'r ddelwedd a osodir gan wallpaper_filename yn cael ei ddangos. Gwerthoedd dilys: "none", "wallpaper", "centered", "scaled", "stretched", "zoom".