Why does green color have FFFFFF as its hex value?

I am trying to create a script that converts a png file into a tiled map and when I was trying to check if the color was green I noticed that every green pixel with the ColorUtility.ToHtmlStringRGB() function returned FFFFFF. Every other color registered properly. Why is it so?!

Found out that I was using the image as a normal map instead of a sprite and now it works.