def allowed_image(filename):
    """ 
    Check each uploaded image to ensure a permissible filetype and filename 
    Takes full filename as input, returns boolean if filename passes the check
    """
    allowed_img_ext = ["JPEG", "JPG", "HEIC"]

    # Ensure file has a . in the name
    if not "." in filename:
        return False

    # Split the extension and the file name
    exten = filename.rsplit(".", 1)[1]

    # Check if the extension is in ALLOWED_IMAGE_EXTENSIONS
    if exten.upper() in allowed_img_ext:
        return True
    else:
        return False