My "modern" clients who live in a split-level wanted a gallery wall of family photos. We decided that their staircase wall was the best place for this since it's open to their first floor living spaces.
I designed this wall for them in CAD which shows the size and color frames they will need to purchase in order to achieve this look. The design placement is based around the centermost part of the visible wall area.
They can be purchased from Pottery Barn here>