HotDog,
the location of the fuel leak and the ignition source do not neccesesarily have to be on the same side of the aircraft. The crosswind from the right may have had a big influence, too. The slope of the ground might have pushed the fuel to left side also, causing the fire to burn mainly on the left side. It is clearly visible in the picture posted above, that the flames at the right engine burn all along from the ground to the pylon, (due to the wind, it is not just flames reaching up to the pylon, but you can clearly see something burning all the way along) while on the left side no evidence is visible, all fire there might be fuel on the ground.
If the problem was located on the right side, it will be covered up as the firemen did a good job to safe that part of the aircraft for investigation...