Wa `alaykum as-salamu wa rahmatullah wa barakatuh

In the Name of Allah, the All-Merciful, the Mercy-Giving

All praise is due to Allah. Peace and blessings be upon His Messenger Muhammad.

The Messenger of Allah (peace and blessings be upon him) cursed a woman who does tattoo and the woman who asks for it to be done for her. The same ruling applies to men, for women have been mentioned because they often tend to do it.

This means that a person who has this tattoo has to repent to Allah the Almighty and to remove it. If it needs a surgical operation and one cannot afford it, then this could be an excuse for him until he can.

Now, if this person, who is qualified for being an imam, knows that tattoo is haram, and has repented to Allah but is not able to remove the tattoo, then he may lead you in Prayer and you should help him get rid of that tattoo. However, if he has not repented, he should not lead you.

Almighty Allah knows best.