The effectiveness of a square boundary array in finite-range, pulse-echo imaging is investigated. The images produced by such an array are quite poor when no additional signal processing is used. It is demonstrated through simulations that a synthetic-aperture signal processing technique called image addition can be used to reduce the sidelobes associated with the square boundary array, thereby improving the image quality. Image addition was originally proposed for narrowband imaging of far-field scenes, but it is also useful for finite-range, pulse-echo imaging. The conclusions are expected to apply to other, nonsquare boundary array geometries.