  We use high-resolution N-body numerical simulations to study the number of
predicted large-separation multiply-imaged systems produced by clusters of
galaxies in the SDSS photometric and spectroscopic quasar samples. We
incorporate the condensation of baryons at the centre of clusters by
(artificially) adding a brightest central galaxy (BCG) as a truncated
isothermal sphere. We make predictions in two flat cosmological models: a LCDM
model with a matter density $\Omega_0=0.3$, and $\sigma_8=0.9$ (LCDM0), and a
model favoured by the WMAP three-year data with $\Omega_0=0.238$, and
$\sigma_8=0.74$ (WMAP3). We found that the predicted multiply-imaged quasars
with separation >10" is about 6.2 and 2.6 for the SDSS photometric (with an
effective area 8000 deg$^2$) and spectroscopic (with an effective area 5000
deg$^2$) quasar samples respectively in the LCDM0 model; the predicted numbers
of large-separation lensed quasars agree well with the observations. These
numbers are reduced by a factor of 7 or more in the WMAP3 model, and are
consistent with data at < 8% level. The predicted cluster lens redshift peaks
around redshift 0.5, and 90% are between 0.3 and 1. We find that the BCG
creates a central circular region, comparable to the Einstein ring of the BCG,
where the central image disappears in the usual three-image and five-image
configurations. If we include four image systems as an extreme case of
five-image systems (with an infinitely demagnified central image), we find that
68% of the central images are fainter by a factor of 100 than the brightest
image, and about 80% are within 1.5"of the BCG.
