Small prints can be captivating, and as others have said, draw the viewer in.
The important thing, however, and a few in this thread seem not to understand this, is that the board the print is mounted on should not be a small board. My wife, Paula Chamlee mounts 6x6, 6x7, 4x5, and 5x7 on the same size mat board as she mounts 8x10s--13 x 15. Small mount board trivialize the work; a larger white space sets the photograph off from the surroundings and makes it feel significant.
Michael A. Smith