Here are the pics of the two:
I always take pictures like this with a grain of salt.
Example: Suppose 1 fin is 1" longer than the other when compared is in that picture. Now suppose you actually put the fins on and find out that the "longer" fin actually slides 1" further onto your foot, due to the size or shape of the foot pocket. Then the fins are really the same length, even though one looks longer.
Foot pocket shape and how it actually fits on your foot - how deep your foot fits into the pocket - seems to me to be an important factor in comparing fin "length".