Photons, which are elementary particles of light, are considered to be point particles in the Standard Model of particle physics. This means that they are considered to have no size or spatial extent. According to our current understanding, photons are described as massless particles with zero rest mass and no internal structure.
However, it's important to note that the concept of "size" can be somewhat ambiguous when dealing with fundamental particles. In quantum mechanics, particles can exhibit both wave-like and particle-like properties, and their behavior is described by a probability distribution rather than a definite position. In this sense, the concept of a well-defined radius may not be applicable to photons.
In summary, photons are typically considered to be point-like particles with no physical size or radius.