docs: add screenshot and add instructions on clock config

docs/docs/intro.md

@@ -16,6 +16,8 @@ You may find yourself asking, do we really need another alternative frontend for
 
 ## Why Photodash?
 
+![Photodash Screenshot](/img/screenshot.png)
+
 I've wanted a good tablet dashboard setup since my first forays into the smart home with SmartThings in 2018. However, I had one specific box I wanted any dashboard I used to be able to check: a focus on being used as a photo frame. We have young children and take a lot of pictures as a result, and if we were going to put a tablet in the living room, we wanted it to display photos the vast majority of the time, with a sprinkling of home control.
 
 I tried various other options to try and meet my needs with an existing solution, including DAKBoard, Tileboard with some heavy customizations I made, and Home Assistant Lovelace with an attempted fork of the animated background card. Those, and others, are great tools, and the default Lovelace frontend has come a long way on its own, but nothing met my use case without compromise. Photo display was, at best, an afterthought. Thus, Photodash was born, after two years of on-and-off development.

docs/docs/user/configurations.md

@@ -12,6 +12,8 @@ A configuration defines a group of basic settings for Photodash. You can create
 ## Configuration Options
 ### Configuration Name
 Give your configuration a unique name. *(Required)*
+### Clock Format
+If you want to display a clock and the current date in the upper left corner of the dashboard, select either a 12-hour or 24-hour format clock here.
 ### Weather Entity
 This dropdown will populate with any weather entities you have configured in Home Assistant. If you would like the current weather conditions and upcoming forecast to show in this Photodash configuration, select the entity from the dropdown.
 ### Background Music Entity