According to StackExchange, such a website would need to get a minimum of 10 questions per day during the beta phase to be considered 'healthy'.. I can not imagine 10 people daily asking unique questions related to pixel art, not based on their own images.
There is are pixel art reddits, facebook groups, multiple large forums, a gallery site, what would stop anyone from asking their questions at one of these places?
It is nice of you to take initiative, but I don't believe the pixel community is in need of a Q/A site...