If you have a display (i.e - TV) which has Google Chromecast connected to it, you can cast (stream) your laptop/computer screen directly into the display you want to show the Photo Wall on.
To do that:
Make sure your TV (or Chromecast) in connected the same Wi-Fi network as the device you are using to cast (your laptop/computer)
On you laptop, open a new tab on Google Chrome and open your Photo Wall link (which can be found in the dashboard).
Click on the three vertical dots in the top right corner of the browser window and select "Cast" from the dropdown menu.
In the "Cast to" window that appears, select the name of your Chromecast/TV from the list of available devices.
Your tab should now be cast to your TV! Make sure to go full-screen to hide the browser frame and to occupy all the available space on the screen.
You can also check this Youtube video explaining how to do it:
Pro Tip - Set the browser to full screen to hide the browser frame so it takes the entire space available on the display. It's also suggested to connect the laptop to a power adapter so the battery won't die during the event.