Myself and others always upload our pictures to the same Dropbox folder. Nis when everr a new picture is uploaded it will be set to your wallpaper

This Trigger fires every time a photo is saved in the folder you specify. NOTE: will process up to 15 photos per polling period.

This Action will update the wallpaper on your Android device from the image URL you specify.

New photo in Dropbox? Set to wallpaper!