Is it a condition for the follower and the imam to stand side by side in congregational prayer, or should the imam stand slightly ahead?

If a man prays with the Imam, it is recommended for him to stand to the Imam's right. The majority of scholars hold that he should stand slightly behind the Imam, at his heel, their evidence being that the Imam's rank necessitates his precedence over the follower. The correct view is that he stands to the Imam's right, aligned with him, neither preceding nor trailing. The evidence for this is the action of Umar ibn Al-Khattab (may Allah be pleased with him) with Abdullah ibn Utbah ibn Mas'ud, where Umar brought Abdullah closer until he made him stand beside him to his right. What supports this is Imam Al-Bukhari's chapter heading: "Chapter: One stands to the right of the Imam, aligned with him, if there are two of them."