# Reasonable: small rotation
M = cv2.getRotationMatrix2D((cx, cy), 7, 1.0)
rotated = cv2.warpAffine(
    img,
    M,
    (w, h),
    borderMode=cv2.BORDER_REPLICATE
)

# Potentially problematic for a chest X-ray:
flipped = img[:, ::-1]