Riot, what are you views on the use of art assets?

Hey Riot! I wish to use an image that was created by Riot games of the shadow isles. My intent is to use as a background for a youtube channel banner. My favorite champion is Mordekaiser, and if and when I decide to create videos, I want the banner to reflect him. The shadow isles seemed like the perfect picture. It would be in conjuntion with other images and text, but overall, I just want to know Riots views on the use of their art assets for this sort of thing.

Here is the image in question http://img2.wikia.nocookie.net/__cb20140803182651/leagueoflegends/images/4/48/Shadow_Isles_concept_4.jpg