add more context to showcase screenshots

SHOWCASE.MD

@@ -1,18 +1,19 @@
 ## Tube Archivist on YouTube
 [![ibracorp-youtube-video-thumb](assets/tube-archivist-ibracorp-O8H8Z01c0Ys.jpg)](https://www.youtube.com/watch?v=O8H8Z01c0Ys)
+Video featuring Tube Archivist generously created by [IBRACORP](https://www.youtube.com/@IBRACORP).
 
 ## Screenshots
 ![home screenshot](assets/tube-archivist-screenshot-home.png?raw=true "Tube Archivist Home")  
-*Home Page*
+*Home Page*: Your recent videos, continue watching incomplete videos.
 
 ![channels screenshot](assets/tube-archivist-screenshot-channels.png?raw=true "Tube Archivist Channels")  
-*All Channels*
+*All Channels*: A list of all your indexed channels, filtered by subscribed only.
 
 ![single channel screenshot](assets/tube-archivist-screenshot-single-channel.png?raw=true "Tube Archivist Single Channel")  
-*Single Channel*
+*Single Channel*: Single channel page with additional metadata and sub pages.
 
 ![video page screenshot](assets/tube-archivist-screenshot-video.png?raw=true "Tube Archivist Video Page")  
-*Video Page*
+*Video Page*: Stream your video directly from the interface.
 
 ![video page screenshot](assets/tube-archivist-screenshot-download.png?raw=true "Tube Archivist Video Page")  
-*Downloads Page*
+*Downloads Page*: Add, control and monitor your download queue.