I need to encode image into binary, send it to server and decode it back to image again. The decoding method is:

def decode_from_bin(bin_data):
    bin_data = base64.b64decode(bin_data)
    image = np.asarray(bytearray(bin_data), dtype=np.uint8)
    img = cv2.imdecode(image, cv2.IMREAD_COLOR)

    return img

We use OpenCV to encode image:

def encode_from_cv2(img_name):
    img = cv2.imread(img_name, cv2.IMREAD_COLOR)  # adjust with EXIF
    bin = cv2.imencode('.jpg', img)[1]
    return str(base64.b64encode(bin))[2:-1] # Raise error if I remove [2:-1]

You can run with:

raw_img_name = ${SOME_IMG_NAME}

encode_image = encode_from_cv2(raw_img_name)
decode_image = decode_from_bin(encode_image)

cv2.imshow('Decode', decode_image)
cv2.waitKey(0)

My question is: why do we have to strip the first two characters from base64 encoding?