Change the color of an image file

colorChange.py

from PIL import Image
import sys
import os

picture = None
picturePath = None

def validateColor(hex):
    return (len(hex) == 7)

def hexToRGB(hex):
    value = hex.lstrip('#')
    lv = len(value)
    return tuple(int(value[i:i + lv // 3], 16) for i in range(0, lv, lv // 3))

def changeColor(oldColor, newColor):
    width, height = picture.size

    for x in range(width):
        for y in range(height):
            current_color = picture.getpixel((x,y))
        
            if current_color[0] is oldColor[0] and current_color[1] is oldColor[1] and current_color[2] is oldColor[2] and current_color[3] is not 0:
                picture.putpixel((x,y), (newColor[0],newColor[1],newColor[2]))

    path = picturePath.replace(os.path.basename(picturePath),'')
    picture.save(path + "new_" + os.path.basename(picturePath))

def help():
    print("colorChange needs 3 arguments: file origColor changeColor\ncolors must be hex values")

if __name__ == "__main__":
    
    if len(sys.argv) == 4:
        picturePath = sys.argv[1]
        picture = Image.open(picturePath)
        
        if picture is not None:
            origColor = None;
            if validateColor(sys.argv[2]) is True:
                origColor = hexToRGB(sys.argv[2])

            newColor = None
            if validateColor(sys.argv[3]) is True:
                newColor = hexToRGB(sys.argv[3])
            
            if origColor is not None and newColor is not None:
                changeColor(origColor, newColor)
            else:
                print("Invalid color")

    else:
        help()

Usage: python3 colorChange.py path/to/image.png "#ffffff" "#000000"

#ffffff -> original color to be changed
#000000 -> new value of color that was to be changed