No. Not correct.
Photoshopping is common enough in photos from KP.
The photo has been 'killed' by media agencies, not the royals. It's still up on their Instagram.
Its been 'killed' not because of a tiny bit of photoshopping, but because it appears to be substantially doctored and as a result, they do not have faith in the veracity of what it claims to represent.
I don't believe a 'kill order' has ever been issued against a photo released by the royals before. Correct me if I'm wrong.