The pictures, showing a few men gathered around a table when the sea eagle was being skinned alive while its legs had been chopped off, were shared on Facebook and in a local newspaper, causing public outcry.
Two people were arrested from the beach resort town of Habaraduwa, 130 kilometres south of the capital Colombo, police officials said, adding, search is on for the remaining three suspects.
Police said the two men were being charged under flora and fauna Act for killing the sea eagle which is a highly protected species according to the local law.
The arrests came a day after a Sri Lankan court ordered the arrest of a popular Buddhist monk for allegedly possessing a two-year-old baby elephant without a license.