Are there illustrative examples where a conventionally "bad bishop" leads its side to a win? I was looking the Chess glossary and two words brought curiosity : bad bishop and big pawn. Where the later being the condition that occurs when you have a bad bishop. One thing i noticed was bad bishop was always defined on end game reference. I don't understand why? Can't you have bad bishop or a big pawn mid-game or relatively early game!(?) 

 Found these images for bad bishop and big pawn on Wikipedia:
 

Hence, I wanted to know if there were any games where big pawn leads a chess player to victory (When enemy has a good bishop) at an international stage?
or rephrasing the above as "occurrences where bad bishop was more significant to victory than a good bishop?"
My understanding is that we call a bad bishop a "big pawn" especially in the endgame to emphasize the fact that the bishop cannot be considered a full piece in these situations. It can't move much. It is very passive. Having such a bishop is a long term handicap.

You are right, these situations can also occur earlier in the game, but there is always a hope that a passive bishop can be traded or become more active when the position opens. 

For instance, in the Dutch Stonewall, the Bc8 is a bad bishop but you can try to trade it by playing Bc8-d7-e8-h5 or via a6 in some cases. Having such a bishop earlier in the game is a handicap, but calling it "big pawn" would be too definitive, the bishop can live again!

*"Occurrences where bad bishop was more significant to victory than a good bishop?"

In the early stages of the game this is very possible and I'm sure we could find examples in the Dutch Stonewall or in the French defense where the Bc8 wins the game. In the endgame, I guess this will only happen if the opponent makes a mistake to turn a bad bishop into a winner. 

Here follows an example, where the bishop in e6 is a "big pawn". White could have taken advantage of that and won the game. But in the end, after White's mistakes, the "bad" bishop wins the game! 

[Title "Max Euwe vs Vera Menchik, Hastings 1930/31"]
[fen "6k1/1p3ppp/4b3/2Pp4/8/4P1P1/B4PPK/8 w - - 0 1"]

1.Kg1 Kf8 2.Kf1 Ke7 3.Ke2 Kf6 4.Kd3?! (4.Bb3!! {Dvoretsky} 4... Ke5 5. f4 Kf5 6. Bd1! {arriving just in time to cover the g4-square} d4 7.Bc2+! Kg4 8.exd4 Kxg3 9. Ke3 f5 10. Bd1 Bd5 11. Bf3+-) 4... Ke5 5.g4 g5! (5... Bxg4? 6.f4 Ke6 7. e4 Ke7 8. Bxd5+-) 6.g3 Bxg4 7.f4+ gxf4 8.gxf4+ Kf6 9.Bxd5 Bc8 10.Bf3? (10.e4!?) Ke7 11.Kc4 Kd8 12.Kd5 b6! 13.c6? (13.Bh5=) Kc7 14.Ke5 Be6 15.f5 Bb3 16.Kf6 b5 17.Kg7?? (17.e4!=) b4-+ 18.Kxh7 Bc2 19.Kg7 b3 20.Bd5 b2 21.Ba2 Kxc6 22.f6 Kd6 23.e4 Bxe4 24.Kxf7 Bd5+! {The "bad" bishop in action!) 25.Bxd5 b1=Q 26.Kg7 Qg1+ 27.Kf8 Kxd5 0-1