A blank wall is perhaps one of the most daunting challenges in decorating. Although there's all sorts of things you could do there - hang a piece of art, add a piece of furniture, paint crazy stripes - it's hard to make a decision when there are so many options. My friend Kim had a similar problem in her eat-in kitchen. She has a blank wall next to the back door that is begging for attention. She's a really great photographer, so she knew that she wanted to hang some of her images on the…