Bromides are chemical compounds containing bromide ion. Bromide ion is formed when bromine atom gains an electron. The examples of bromide salts are sodium bromide, potassium bromide, cesium bromide etc. Bromide is also present in typical seawater with a concentration of around 65 mg/L. One important salt of bromide is silver bromide which is used in photographic films.
This video explains how to test the presence of bromide ion in a given salt.