It's definitely possible but there is a bit of deliberation involved.
There's 2 ways of doing this:
- Use a list of rares (by mining wowhead) similarly to how the addon uses a list of bosses (provided by LibBossID)
- Use API to determine if the mob killed was a rare.
There's pros and cons to both methods.
List pretty much ensures you will not miss a rare screenshot (if your list is complete)
but you can end up with screenshots when others (in combatlog distance) kill a rare.
I'm testing a method that doesn't rely in a hardcoded list but it is a bit hard to find rares on demand
Anyway I'll probably post some code tomorrow or the next day for both methods and dlui can decide if and which he'd like to use