Well, if you've checked that this one pixel is definitely of the same color as what you put in the csv (125,125,125), then it's probably a format error. Did you save cultures.bmp as a 32-bit image maybe ?There are cultures.csv and cultures.bmp in input, and both their RGB are same. I don't know what is wrong. Can you help me?
If you still can't find the problem, you can send me your 2 cultures files and I will take a look.