By Andy Blackmore Kate’s doctored photo has plunged us into a trap where we question nothing because we’ve already dismissed it as fake. That’s where the truth goes to die, argues Andy Blackmore Again, against my better judgement, I feel it is my professional duty as a picture editor to add a further two-pence worth on the latest episode in the “Kategate” saga: the sudden appearance of an image of the Princess of Wales visiting a farm shop. I’m still gripped by one overwhelming question: why? Why didn’t the Princess of Wales just cut the head off the snake and issue the original, unedited imag…