Parents gathered outside the school from 7.30am on Thursday to protest following the lesson.
Community figurehead Imam Mohammed Amin Pandor spoke to those who gathered outside the school on Carlinghow Hill, Batley.
He said: "What happened here, we are disgusted.
"What has happened is totally unacceptable and we have made sure they are aware.
"The teacher has been suspended. They can't just sack him, they need to do their due process.
"We've asked for an investigation, an investigation to be independent.
"We are going to work with the school to make sure things like this don't happen."
The Imam said he had spent time meeting with the school's headteacher Gary Kibble on Thursday.
In a statement, Mr Kibble said: "The school unequivocally apologises for using a totally inappropriate resource in a recent religious studies lesson.
"The member of staff has also given their most sincere apologies.
"We have immediately withdrawn teaching on this part of the course and we are reviewing how we go forward with the support of all the communities represented in our school.
"It is important for children to learn about faiths and beliefs, but this must be done in a sensitive way.
"The member of staff has been suspended pending an independent formal investigation.
"The school is working closely with the governing board and community leaders to help resolve this situation.
Officers from West Yorkshire Police attended to ensure the protest remained peaceful.
A force spokesman added: “We are aware of a small demonstration at the school, which is still ongoing. Local neighbourhood officers are in attendance."
Kirklees Council said it was aware of issues raised by parents this week.
Councillor Carole Pattison, Cabinet Member for Learning, Aspiration and Communities, at Kirklees Council, said: “Batley Grammar is an academy school so the council has a very limited role in its running but we are aware of issues raised by parents this week.
"We are pleased to see that the school has taken swift action to resolve the issues alongside the local community. They have apologised, taken immediate action on teaching materials and they are reviewing the relevant processes."