There may be a couple problems. Many times a salt bridge erects over the bottom of the salt bin. Since the brine solution is made in the bottom, if the salt can not reach it, because it has bridged about half way up, you will not be softening your water. You can break the salt bridge with a handle from a broom. They form because of the moisture in the brine tank.
It looks from the inside like your salt bin is full, but if your not using salt, its probably not working. Then sometimes the pipe that takes the salt to the resin tank can get clogged. Its much harder to fix, especially if the softener is a single unit, instead of brine tank and resin tank.
The real question is, how old is the unit. You may not want to spend too much money fixing up an old one. Some of the new ones have electronic sensing, to determine the proper amount of salt and regeneration cycle.