What is the difference between photons from an electron and photons from a proton? So, I am trying to get my head 'round the workings of electromagnetism.
Pretend I am 5 years old.
Protons send out photons to electrons that cause the electrons to accelerate towards the proton, and vice versa. Is that correct?
When those same photons from protons are received by protons though, the recipient protons move away.
What's the difference between the 'proton-photons' and the 'electron-photons' fundamentally?
 A: The description of EM in terms of (virtual) photons is very good for describing/predicting scattering cross sections and decay rates, which is what particle physics deals with most of the time.
It is not very good at describing attraction and repulsion - which is the first thing people think about forces in everyday life.
So for something like Rutherford scattering the first order cross sections for electron-proton scattering and positron-proton scattering, involving interchange of one virtual photon, are exactly the same. There is a factor $Q_1 Q_2$ in the amplitude which is $+1$ for $e^+p$ and $-1$ for $e^-p$, but this is squared to get the probabilty.

If you go to second order, exchanging two photons, the factor in the amplitude is  $(Q_1 Q_2)^2$, even less promising. But the interference term between the two amplitudes is now $Q_1^3 Q_2^3$ so this does produce a difference between the two charges.
Extending this to many orders, such differences produce the attraction/repulsion result which is the main feature of everyday electrostatics.
So: the virtual photons from positive and negative charges are the same. But the way in which they interfere with other virtual photons involved in other exchanges produces, eventually, an attraction/repulsion difference.
