Light is very strange. Sometimes it is best to think of light as a series of waves. At other times, it is useful to think of light as a swarm of particles. When we think of light as particles, we call those particles of light “photons”.
Photons are the carriers of all forms of electromagnetic (EM) radiation, not just light. The different types of EM radiation correspond to different amounts of energy per photon. Gamma ray and X-ray photons have the most energy, radio frequency photons have the least energy, while ultraviolet, infrared, and visible light photons have intermediate energies.
Photons travel at the speed of light, which is 299,792.458 kilometers per second (about 186,282.4 miles per second)! Photons don’t have any mass, nor do they carry an electrical charge.Because of their dual nature as particles and waves, photons are often shown as squiggly lines SOURCE : WINDOWS TO THE UNIVERSE