The chick whose giant ass made it on one of Kanye West's 'Life of Pablo' covers owes a HUGE thank you to Kim Kardashian for picking her cakes out of a lineup.

The model's name is Sheniz Halil ... and she's already got a pretty solid following online ... not hard to see why.

Sources close to Kanye tell us 'Ye wanted Kim involved in his new album so he let her pick the butt model. As they say ... do what you know, and Kim knows ass.

We're told his art team put a bunch of photos in front of Kim and she picked Sheniz simply because she thought she had the best butt.

Thankfully, Kanye didn't question his wife's prowess.