  The intrinsic sizes of the field galaxies with I<26 in the Hubble and ESO-NTT
Deep Fields are shown as a function of their redshifts and absolute magnitudes
using photometric redshifts derived from the multicolor catalogs and are
compared with the CDM predictions. Extending to lower luminosities and to
higher z our previous analysis performed on the NTT field alone, we find that
the distribution of the galaxy disk sizes at different cosmic epochs is within
the range predicted by typical CDM models. However, the observed size
distribution of faint (M_B>-19) galaxies is skewed with respect to the CDM
predictions and an excess of small-size disks (R_d<2 kpc) is already present at
z~ 0.5. The excess persists up to z~3 and involves brighter galaxies . Such an
excess may be reduced if luminosity-dependent effects, like starburst activity
in interacting galaxies, are included in the physical mechanisms governing the
star formation history in CDM models.
