they are both the same site. FAA was first, then they made pixels because it's universal, and they want that to be the mother site. it has more products and is easier to spell. you can be signed in one or the other, just make sure you don't mix them up because sponsoring words only works on the site your logging into (pixels for pixels, etc)
duvet covers can only be sold on images 5000x5000px or over in any direction. if you don't have that size, you can't sell them. by color is hard because you may not have those colors. there shouldn't be any real distortion, you would need a screen grab.
---Mike Savad
MikeSavad.com