  A theorem on subwavelength imaging with arrays of discrete sources is
formulated. This theorem is analogous to the Kotelnikov (also named
Nyquist-Shannon) sampling theorem as it represents the field at an arbitrary
point of space in terms of the same field taken at discrete points and imposes
similar limitations on the accuracy of the image. A physical realization of an
imaging system operating exactly on the resolution limit enforced by the
theorem is outlined.
