filter.py

from PIL import Image

# Open image
image = Image.open('image.jpg')

# Filter
def filter(image):
    # Get image dimesions
    width, height = image.size

    # Create a white RGB image
    new_image = Image.new("RGB", (width, height), "white")

    # Filter magic happens here

    return new_image

# Show result
new_image = filter(image)
new_image.show()