[en] This work concerns the radiochemical measurements of the photonuclear reaction yields of light nuclei (⁷Be, ¹⁰Be, ²²Na, ²⁴Na and other heavier nuclei) from various targets over the periodic table in irradiations with bremsstrahlung beams having maximum end-point energies (E₀) up to 1200 MeV. The results were compared with proton cross sections for formation of these nuclides because it is expected that the difference of their initial steps might be reflected in the yield profiles of the fragmentation products. It would also be interesting to find some clues for distinctions whether a heavy nuclear cluster is formed as a result of emission with a certain kinetic energy (fragmentation) or as a result of many nucleon-emission (spallation residue), from an excited nucleus produced by photon irradiation. It was found that there exist direct emissions of ⁷Be and ²⁴Na, as indicated by their reaction thresholds for several targets. The target mass (A_t)-dependence of the yields at E₀ = 1000 MeV was found to have two components. The first component could be explained by spallation, the second, by fragmentation. However, the extents of the relative contributions are different in different targets. The relation between the yields of light nuclei could also confirm this and those estimated by the Rudstam empirical formula for spallation. The profile of the A_t-dependence of the ⁷Be and ¹⁰Be yields was found to be quite different, reflecting the difference of (N/Z), neutron to proton ratios, both the products and targets. Furthermore, the A_t-dependence of the yields at E₀ = 1000 MeV was found to be comparable in shape with the A_t-dependence of the proton cross sections at E_p = 400 to 600 MeV. (author)