>>/8208/
Okay, I think I get it now. 

> Other times, "screen cap" refers to the fact the image board was capped, or a pony encountered a 'cap of something from our world.

Still, whole episodes is what I maintain.
On the main fandom boorus, like Twibooru, I believe it is this way as well:
https://twibooru.org/search?q=screen+cap
> Short description: Screen-captures from official My Little Pony content