I am from Galicia and shot #3 is definitely not representative from Galician Carnival. Galicia is a gorgeous destination, especially during Summer, but don't expect to have the kind of fun that the guy in photo #3 is having :-) Here are a couple of videos that provide a much better representation of what Galicia currently is: https://www.youtube.com/watch?v=uG1hkCzefL0 and https://www.youtube.com/watch?v=ZtUqecPNXgI
You can definitely find popular festivals in Galicia where getting drunk is the main goal, if that's your thing. I'd say it's a waste of time, though, given how beautiful and great Galicia is. Better to get wasted closer to home.