If Selfie is asked to upload then it can be at anywhere depending on the location and the place you are at the moment, so if it is on the road, in the car, or in the room they would see it and accept it. My brother, if the amount to withdraw is big and they need the KYC to clarify everything before allowing you to withdraw the money, it is better you do it to withdraw the money before they changed their mind because this casino owners are always looking for one thing to the other to decline and cancel large withdrawal.
But I don't really like casinos stressing someone at the time of withdrawing his win with KYC. KYC would done before the withdrawal so things will be easy for the gambler to do.
I think they won't care if where you are or what is your background as long as they can see your face clearly but like the user above said, there are a few gambling site who ask you to selfie next to a street sign. I think this was a lil bit insane and can be dangerous too because your phone might get snatched or you might get hit by a car.
If I'll be asked about this, I don't think I can do this immediately because there is no street sign on the place where I live but I need to travel in the town first lol. Usually, KYC is asked if the withdrawal amount is huge. I think that is for them to know that it wasn't a laundered money and also to know that the original owner still controls the account. There are still gambling sites who can ask a KYC at the start or even if the withdrawn money is only small.