Should imam always be spelled with a capital M?

The word "imam" is a noun and generally should not be capitalized unless it is the first word of a sentence or part of a proper noun.

Here are some examples:

* Correct: The imam led the prayers.

* Correct: I met with Imam Ali.

* Correct: The imams of the mosque are respected leaders.

However, when "imam" is part of a specific title or name, it should be capitalized:

* Correct: Imam Ali (a specific person's name)

* Correct: The Grand Imam of Al-Azhar (a specific title)

In general, the rule of thumb is to capitalize titles and names, but not common nouns.