TOS never showed a photon torpedo onscreen outside of the VFX of it being fired.
TMP had a graphic on Chekov's Weapons control panel that showed a status of when a torpedo was in the tube; but still didn't show any portion of the actual 'load' process.
It wasn't until STII:TWoK we got the (IMO) ridiculous scene that showed torps being manually loaded.
Given the few times (and speed) that they showed the TOS 1701 able to quickly fire a full torp spread; I find it hard to believe (and hated) that 'Photon Torpedoes' where manually loaded per the depiction in STII in the manner they were; and now somehow had a physical casing. Watching TOS on TV growing up, I always assumed they were 'balls' Anti-Matter Energy generated IN the 'tube' and quickly released/fired before the energy encasing the antimatter dissipated.
The above said, clearly (per Episode 13 of ST: D) they are physical torpedoes with cases and warheads attached.