The medic was seen removing protective clothing before spitting on three pictures in the communal hallway of the block of flats in Jaffa in Tel Aviv.
When confronted, the medic claimed the imagery was a form of idolatry forbidden by the Hebrew Bible.
Israel’s ambulance service said it “strongly condemned” his actions.
The Magen David Adom (MDA) employee, it said, was “unworthy of representing the organization” and was dismissed immediately.
The incident happened on Sunday when the medic went to the block – whose residents are all Christian, according to media reports.
Security camera footage shows the worker removing his mask and overalls before turning around and spitting three times in succession.
He is then seen putting his mask back on and getting into a lift.
As he was leaving the building, the medic was confronted by a tenant who filmed their exchange on a mobile phone.
When the tenant asked why he spat at the pictures, the worker replied: “In Judaism, this is foreign worship.”
In a tweet, the ambulance service said it “strongly condemned” what happened, adding that it works with, and employs, members of all religions and sections of society.
This is a severe incident for which the employee was called to a disciplinary hearing by MDA's management. The employee was informed that he is unworthy of representing the organization and wearing the uniform, and that he is being dismissed immediately.
— Magen David Adom (@Mdais) November 16, 2020
