  To probe the progenitors of the numerous massive spirals requires to dissect
distant galaxy properties through spatially-resolved kinematics, detailed
morphologies and photometry from UV to mid-IR. So far IMAGES is the only
representative sample studied that way. Six billion years ago, 50% of spiral
progenitors were experiencing major mergers, evidenced by the combination of
their peculiar kinematics and morphology. IMAGES provides the observational
point of the spiral rebuilding scenario, which agrees with predictions from the
LCDM. It reconciles the disk formation or survival with the observed merger
rate and allows to reproduce realistic galactic disks with sufficient angular
momentum. Several consequences are expected in the Local Universe, because
ancient major mergers had let imprints in galaxy haloes, including the most
spectacular cases of NGC5907 and M31. An ancient merger in the later galaxy may
have left many debris within the Local Group.
