BBC news channel just had a live picture the same angle as the photo nearest above, and also video from a helicopter tour above it after the fire was out, showing smoke deposited on both sides of the fuselage but more on the left about adjacent to the leading edge, the script saying a fire in one engine
Edit 0125: just showing it again, again saying left engine on fire as preparing for takeoff, and this time also quoting unnamed FAA spokesman also saying left engine fire