  Recent microscopic and phenomenological calculations of giant dipole
resonances for A <= 56 nuclei are presented. The derived photodisintegration
cross sections are exhaustively compared to the photonuclear data available to
date. An accurate description of the data is found. Our new calculations are
also compared with the previous and widely-used estimates of Puget, Stecker and
Bredekamp. The present calculations also include all the possible paths down
the nuclear chart. The impact on the photodisintegration of ultra-high-energy
cosmic rays (UHECR) is illustrated for a Fe source with typical energies of
10^{20-21} eV. At energies around 10^20 eV, the new cross sections are found to
modify the UHECR photodisintegration rates. At energies around 10^21 eV, it is
recommended to solve a full reaction network to estimate the
photodisintegration rate of the UHECR.
