How silver halides sensitizes by photon?

I think it would be bromide(Silver Bromide) because Silver Bromide was used in films for cameras before they all became digital cameras.

Silver halides are essential for developing photographic film.

i just leaning

There are three silver halides used: silver bromide, silver chloride and silver iodide. Silver chloride doesn't absorb very much light and silver iodide is hard to develop. So they use silver...

All I know is, they change their structure when exposed to light.