Of course there's always hanging artwork gallery style which is a little bit more eclectic and random than this version. We love how clean this version looks, especially for a small space where a normal gallery style hanging could become chaotic and overwhelming. And because the images are small, they provide a pop of color in a neutral space and also invite people to stand close to get a good look at the image, instead of needing to step back to get a good look (in some small spaces there's no room to take a step back).
Some places we'd love to see this arrangement: in a long hallway, a small bathroom (provided that there's good ventilation, along one wall of a tiny kitchen, behind the couch in a living room.
This could also be a great way to display favorite postcards (we collect them, so we've got shoeboxes full) in a more formal way. The Ikea Ribba Frames come in square silver but have larger mats cut.