ちゃんと変換されていると思うけど、どうよ？

#include<stdio.h>
FILE*R,*S;int i=54,h,s,Y,X,t,T,G,B;main(c,v)char**v;{R=fopen(v[1],"rb");S=fopen
(v[2],"wb");for(;i--;)putc(getc(R),S);fseek(R,18,0);fread(&s,4,1,R);fread(&h,4,
1,R);fseek(S,2,0);i=s%4;X=1078+s*h+h*(4-i);fwrite(&X,4,1,S);fseek(S,10,0);Y=
1078;fwrite(&Y,4,1,S);fseek(S,28,0);X=8;fwrite(&X,2,1,S);fseek(S,54,0);fseek(R,
54,0);for(;B<256;B++)putc(B,S),putc(B,S),putc(B,S),putc(0,S);for(X=s*h;X--;putc
((T+B+G)/3,S))B=getc(R),G=getc(R),T=getc(R);for(t=0;t<4-i;t++)fputc(0,S);fseek(
R,i,1);}