Lord Siva is depicted in many images like the one above as wearing a
garland of snakes around his neck. There is a deep symbolism hidden
behind this.
Lord Siva is know as Pasupathinath, the lord of all creatures.
Being a lord of the animals he has complete control on their
behavior. Since a snake is one of the most feared and dangerous
animals in the world, the garland of snakes around the neck firmly
establishes this fact even the snakes fear Him and remain under his
control.
The snake stands for all the evil and demonical nature in the
world. By wearing the snake around his neck, Lord Siva gives us the
assurance that no evil can touch us or destroy us once we surrender
to him, seek his protection and worship him with deep
devotion.
The snake also stands for the power of kundalini, which is
described as a coiled serpent lying dormant in the muladhara chakra
of all human beings and descends upwards when one starts ones
spiritual journey and becomes increasingly divine oriented. The
snake around the neck of Siva conveys the meaning that in him the
kundalini not only has arisen fully but is also actively involved in
the divine activity by keeping an eye on all the devotees who
approach Siva with their individual problems.
The snake also stands for all passions and desires. By wearing
the snakes around his neck, Lord Siva conveys the message to all his
devotees that He has overcome all desires and is in full control of
Prakriti, or maya and its various machinations.