Riot has a 'manifesto' that lists five ideals we strive for. The fifth is 'Stay hungry, stay humble' and under that you'll find the following description:
We strive to be humbitious – ambitious and humble.
Complacency kills innovation, but ambition kills complacency.
We humbly seek and accept feedback.
We credit the larger team: the families, teammates and players who make it all possible.
And we believe there’s always more we can do for players.
So much in the same way attention isn't drawn to the engineers, tech-artists, dev managers etc. we don't credit any artists on the platform. Rather we focus on the product and the player experience. The reality is that everything we create is the result of a huge team effort and we want to remember that at all times. I'm quick to credit artists here on the forums if someone is looking for more of their work or wants to get in touch to ask about art etc. but they aren't contracted artists creating work in a vacuum, they're game developers working collaboratively to bring players an experience.
Working on LoL is a huge privilege, we are given the trust and expectations of millions of players around the world, and we want to always remember we get to do this because of you.