Although photons can be extremely energetic and each form of energy is inseparably associated with gravitation, the Theory of Special Relativity nevertheless assumes that the gravitation of photons - always supposed to be static in nature - is vanishingly negligible. For this reason the photon’s gravitation is completely ignored in that theory. This paper, however, casts doubt on the correctness of this assumption and will examine the actual role played by gravitation in electromagnetism. In the course of this paper, an analysis will lead to the new insight that the gravitation of a photon is as dynamic as the photon itself, but static gravitation does not exist for photons. The dynamic gravitation of a photon appears as gravitational radiation locally bound to the photon and is in close interaction with the photon’s electromagnetic radiation. Dynamic gravitation represents the hitherto unknown physical quantity acting in an opposite manner to electrodynamics, thus closing an evident gap in physics. Furthermore, it will be shown that dynamic gravitation determines the physical properties of photons, such as the speed of light, and must therefore be taken into account with all associated physical considerations. The dynamic gravitation of photons is produced by gravitational quanta, and thus appears in quantised form. Consequently there must exist exactly the same number of gravitational quanta as there are of photons themselves. It is therefore necessary to rethink the physics of photons.