Emission electron microscopy was used to study the electron emission observed under the passage of a tunnel current through a silver nanoparticle film when a voltage is applied to it. The electron emission originates from separate emission centers emitting photons as well. The electron emission centers are visualized as separate spots in an emission electron microscope. A deformation of shape and size of these spots was studied at various applied voltages. It enables the energy spread of electrons emitted from an individual emission center or at least the width of its most intensive part E as well as the magnitude of electric field E near this center to be estimated. It has been shown that E comprises 0.5-0.6 eV, and E<<10(7) V/cm. The latter result means that the electron emission is not the field emission. (C) 2010 Elsevier B.V. All rights reserved.