Adding a background to a Powerpoint Presentation: (decide which set of instructions applies to the version of PowerPoint you are using).
PowerPoint Version (a)
Format > Slide Background > Fill > Picture (small window top navigation) > Choose a Picture > Apply to All or Apply.
PowerPoint Version (b)
Design > Background Styles > format Background > Picture or Texture Fill > Insert from ... > {Choose Photo} > Insert > Apply to All (if applicable)
