The directions here are what I followed to turn my raspberry pi and 7" pi screen into a photobox.

**Step 1 - Setup **

Install Raspiberry pi OS (full) onto an SD card and install in your Pi.  Bootup, run raspi-config, and get everything setup the way you like it.  

**Step 2 - Screen **

Follow directions [[https://www.instructables.com/Raspberry-Pi-Touchscreen-Setup/|here]] to setup the screen

**Step 3 - Mount network drive on Pi**

As discussed [[https://access.redhat.com/solutions/448263|here]] edit 
  /etc/fstab, 
add the line:
  //192.168.1.110/public/photos   /diskstation_share   cifs  _netdev,username=guest,password=,dir_mode=0755,file_mode=0755,uid=500,gid=500 0 0
note that _netdev is needed for network shares.

also, i followed the instructions here [[https://askubuntu.com/questions/1081601/how-to-fix-fstab-samba-mounts-not-loading|here]] and created the file
  /etc/network/if-up.d/fstab
with the lines
  #!/bin/sh
  sleep 30
  sudo mount -a
Note that the sleep command is a hack that allowed the Pi to settle its network connectivity before it attempted to mount the network folder

**Step 4 - Slide viewer **

following the directions [[https://www.raspberrypi.org/forums/viewtopic.php?t=199320|here]], I created the file runslideshow.sh on the ~/Desktop with the following lines
  #!/bin/sh
  cd /home/pi/diskstation_share
  feh -Z -z -F -D 300 --hide-pointer --auto-rotate --recursive
Note that the recursive allows the directories to be searched recursively.  

To make sure it autostarted correctly, I followed the directions [[https://learn.sparkfun.com/tutorials/how-to-run-a-raspberry-pi-program-on-startup/method-2-autostart|here]] and created a .desktop file at /home/pi/.config/autostart that contains
  [Desktop Entry]
  Type=Application
  Name=runslideshow
  Exec=/home/pi/Desktop/./runslideshow.sh
  
  
**Step 5 - Schedule screen dimming **

To schedule screen dimming, open the scheduler with
   crontab -e

and add the following lines
   0 7 * * * sudo sh -c "echo 255 > /sys/devices/platform/rpi_backlight/backlight/rpi_backlight/brightness"
   0 21 * * * sudo sh -c "echo 12 > /sys/devices/platform/rpi_backlight/backlight/rpi_backlight/brightness"
which brightens the screen at 7:00 and dims the screen at 21:00.  Note that 255 is max brightness and 0 is minimum (off).  


**Step 6 - Enable right click as a long click **

Modifying the directions from [[https://fmirkes.github.io/articles/20190827.html|here]], run the commands

   sudo apt install build-essential libevdev2 libevdev-dev
   git clone 'https://github.com/PeterCxy/evdev-right-click-emulation.git'
   cd 'evdev-right-click-emulation'
   make all
   sudo cp 'out/evdev-rce' '/usr/local/bin/'
   sudo chmod +x '/usr/local/bin/evdev-rce'
   
Then navigate to ~/.config/autostart, create the file: evdev-rce.desktop, and fill it with
   [Desktop Entry]
   Version=1.0
   Type=Application
   Name=evdev-rce
   GenericName=Enable long-press-to-right-click gesture
   Exec=sudo /usr/local/bin/evdev-rce
   Terminal=true
   StartupNotify=false