import cv2

file_path = "test2.bin"
img = cv2.imread('grayscale_gradient_half.png', cv2.IMREAD_GRAYSCALE)

height, width = img.shape
vals = []

for i in range(height):
    for j in range(width):
        k = img[i, j]
        vals.append(k)

with open(file_path, "wb") as file:
    file.write(bytes(vals))