apart from that, I think one of these pictures is grayscale while the other is RGB, and you’re accessing the RGB one (<vec3b>) as if it was grayscale (<uchar>).
that explains the horizontal stretch by a factor of 3.
your snippet of code isn’t enough to diagnose that properly. this is what I figured out from the little bit of info you did share. be forthcoming. don’t make this like pulling teeth.