Alec Baldwin -- Photog Claims ... I Could've Had Alec Arrested!

The photographer who got into it with Alec Baldwin in the Hamptons on Sunday claims police were prepared to arrest Alec ... until he decided to let it all go.

As TMZ first reported, Alec went ballistic on a photog who was shooting him with his wife, Hilaria and kid in a park.

The camera guy in question (his name is Matt) says he was shooting the Baldwins from far away when Hilaria, Alec's wife, started screaming at him -- and before long, he claims Alec started pushing and shoving him.

Matt claims the first officer on the scene saw Alec grab him and put him in a headlock -- and the officer was ready to arrest Alec on the spot, but Matt says he told the cop he did not want to press charges.

TMZ also spoke with a close friend of the Baldwins ... who says the whole headlock claim is total BS. The friend also questioned the pap's credibility because he called Hilaria a "bitch" and a "whore" when she attempted to protect her child from the photog.