We found that this line was taken from Mamata's speech given at the United India Rally on January 19 in Kolkata. The rally was attended by several opposition leaders like Arvind Kejriwal, Akhilesh Yadav, Tejashwi Yadav, Farooq Abdullah, MK Stalin, N. Chandrababu Naidu, HD Kumaraswamy, etc.
We were able to find the video of Mamta Banerjee's speech in which she can be heard saying "Imaan ka Naam hai Musalmaan (The other name of faith is Muslim)". You can watch the relevant section of her speech here at 20:19:
We found that her statement was taken out of context to project as if she is only praising Islam and ignoring other religions. However, he full statement was "Tyaag ka Naam hai Hindu, Imaan ka Naam hai Musalmaan, Pyaar Ka Naam hai Isaai, Sikho ka Naam hai Balidaan: Ye Hai Humara Pyaara Hindustan" which can be roughly translated to "The other name of Sacrifice is Hindu, the other name of faith is Muslim, the other name of love is Christianity and the name of Sikh is Sacrifice: This is our lovely Hindustan".
The viral image is clearly misleading as a part of Mamata Banerjee's speech has been extracted deliberately to spread a false narrative. She talked about all the religions like Hinduism, Islam, Christianity, Sikhism.