  Basic considerations of lens detection and identification indicate that a
wide field survey of the types planned for weak lensing and Type Ia SNe with
SNAP are close to optimal for the optical detection of strong lenses. Such a
``piggy-back'' survey might be expected even pessimistically to provide a
catalogue of a few thousand new strong lenses, with the numbers dominated by
systems of faint blue galaxies lensed by foreground ellipticals. After
sketching out our strategy for detecting and measuring these galaxy lenses
using the SNAP images, we discuss some of the scientific applications of such a
large sample of gravitational lenses: in particular we comment on the partition
of information between lens structure, the source population properties and
cosmology. Understanding this partitioning is key to assessing strong lens
cosmography's value as a cosmological probe.
