After bowing from Ruku when praying with a Imam is it a sunnah after the Imam saying Sami'allaahu Liman Hamidah for a person also to say it against after the saying of the Imam?

Yes, it is a recommended practice (sunnah) for a person praying behind an Imam to say "Sami'allaahu Liman Hamidah" after the Imam says it. This phrase means "Allah hears the one who praises Him" and is said when rising from the bowing position (ruku) in prayer. It is a way of acknowledging and affirming the praise of Allah by the Imam.