An accelerated charged particle will emit radiation perpendicular to the direction of acceleration.

http://physics.weber.edu/schroeder/mrr/MRRtalk.html It seems reasonable to think that accelerating a charged particle changes the position of it's field with respect to it's original position and that change propagates at C. I propose that change is what we call a photon and it will propagate without the need of virtual particles as the medium. The medium is the charged particle's own field. The particle must be accelerated with respect to any observer to emit radiation. If the observer is accelerated at the same rate as the particle then the field lines of the observer change at the same rate as the particles and therefore the observer does not see the particle emitting radiation.

It should be understood that a charged particle has an electric field extending from it three hundred and sixty degrees in all directions. The diagram below is a simple illustration to show how a photon is formed.

The vertical blue line above the blue stationary charged particle represents the collapsing (at C) electric field. The red dashed line represents a changing electric field. The red line above the red accelerating charged particle represents an expanding (at C) electric field. The angle of the dashed red line is just to show that the energy of the photon is dependent upon the acceleration of the charged particle. It should be noted that accelerating an atom or molecule will produce wave fronts according to the number of charged particles involved. To an observer the red dashed line would appear as the magnetic component of the photon and the red line as the electric component of the photon. It should be understood also that a three dimensional picture of the photon would resemble an expanding torus. Using this picture of the photon I will explain the photon double slit experiment and the electron double slit experiment.

In the photon double slit the experimenter designed the emitter device to emit a single photon, but according to the above description of the photon the experimenter was releasing a complete wave that would always pass through a single or double slit producing the corresponding interference pattern.

In the case of the electron double slit the details of exactly how the devise was designed is relatively inadequate. The emitter releases an electron that is accelerated toward a positive plate that has the double slit. Again, from the above, we know the electron will produce a wave that will pass through a single or double slit producing the corresponding interference pattern.