Hello, I am looking to buy a frame for a 16x20 picture. I want the mat opening to be 16x20, so I probably need an 18x24 frame, and the frame has to be espresso. I like some of the frames on Pottery Barn, but, they are not large enough. We looked around town today, but did not find anything that we liked. Anyone know of some good places to buy from online? Thanks!