/3/ - 3DCG

>>478442
Don't do this

Normal maps are designed to be used one way, the way they were baked, flipping them on Y flips the Green channel making them display incorrectly

and Rotating does the same thing to both the Red and Green Channel

G = Y vector
R = X vector of a surface normal

These shouldn't be touched, But If this does happen, you can change the settings in engine to invert the channels or go in a manually invert the G or R channel to fix this but that's a waste of time.
Instead use this if the maps don't match up (though that doesn't seem to be the problem in his image):