automation: 
 - alias: "New wallpaper update"
 trigger:
 platform: event
 event_type: folder_watcher
 event_data:
 event_type: created
 action:
 service: pyscript.update_wallpaper_options
 data_template: 
 action: 'Add'
 entity_id: input_select.wallpaper_selector
 file: "{{ trigger.event.data.path }}"

def update_wallpaper_options(action = None, entity_id = None, file = None):
 """Updates the list of wallpaper options each time a new file is added to the folder"""
 if file != None:
 file = file.split('/')[-1] #Get the file name (change background image already point to the correct path) 
 current_options = hass.states.get(entity_id).attributes['options'] #get the current options 
 if action == 'Add': 
 current_options.append(file) #Append the file name to the current options 
 service_data = {'entity_id' : entity_id, 'options': current_options}
 hass.services.call('input_select', 'set_options', service_data) #call the service to update the options of the entity 

 wallpaper_selector: 
 name: Wallpaper selector 
 options: 
 - Theme Wallpaper