Can the B field of a photon be affected by the gravitational field of another photon?
Yes, everything is affected by gravity. Allthough in this case, the effect would be exceedingly small, of course. Many orders of magnitude smaller than what is experimentally measurable.
Two photons can also interact via the electron & positron in so-called photon-photon scattering. This would be a much stronger effect.
Thanks , very interesting
Separate names with a comma.