It isn't. Remember this: Light goes slower when it's lower. Gravity is there because of this. If you were in a room where the lower optical clock went at the same rate as the upper optical clock, your pencil wouldn't fall down.
It doesn't. The energy is where the four-potential is. E is where the four-potential varies spatially, B is where it varies over time. The four-potential is at a maximum in the middle of the photon where E and B are zero. See the Wikipedia Aharonov-Bohm article, which says Feynman wished he’d been taught electromagnetism from the perspective of electromagnetic potential rather than electromagnetic fields. I wish everybody was taught from that perspective. IMHO most physicists today don't understand electromagnetism, just as they don't understand gravity.
Yeah and You do ? You must be a "Wunderkind"... "light gets slower"... You must be the first guy, trying to convince us, that light in vaccum has varying speeds...