Calculations and analysis of an extended x‐ray source image with a 2D focusing geometry are presented. Based upon the calculations for an x‐ray point source image (Paper Ia), theoretical expressions are derived which reveal the contributions from both the Bragg and the optical (Fresnel) diffractions to the intensity distribution of the image at the focal plane. That is, for a given focusing geometry, the intensity distribution of the image of an extended source consists not only of the crystal rocking curves for a bent crystal, due to the Bragg diffraction; but also of the optical diffraction, the Fresnel integral, due to the phase correlations of the thickness and the spatial extent of a doubly bent crystal. The contribution from the optical diffraction depends solely upon the bent crystal focusing geometry. The relationship between the source and the image at the focal plane is obtained, and the intensity distribution of an extended x‐ray source image with a 2D bent silicon crystal is given. ©1995 American Institute of Physics.