How To Change A Section』s Background Image
Click on the Section Settings handle to enter the Section SettingsGo to Style > Background > Background Type > ClassicUnder Image click the + sign and choose your image.
How To Change An Entire Page』s Background Image
Click the cog icon in the lower left of the editor Panel.Click the Style tab.Click the pencil icon next to Background Type.Under Image, click the + sign and choose your image.