chatGPT 通知我，PIL 的 resize 的默认插值是 BILINEAR
事实真是如此吗？
看一下 PIL 的源码：
PIL/Image.py
def resize(self, size, resample=None, box=None, reducing_gap=None): """ Returns a resized copy of this image. :param size: The requested size in pixels, as a 2-tuple: (width, height). :param resample: An optional resampling filter. This can be one of :py:data:`Resampling.NEAREST`, :py:data:`Resampling.BOX`, :py:data:`Resampling.BILINEAR`, :py:data:`Resampling.HAMMING`, :py:data:`Resampling.BICUBIC` or :py:data:`Resampling.LANCZOS`. If the image has mode "1" or "P", it is always set to :py:data:`Resampling.NEAREST`. If the image mode specifies a number of bits, such as "I;16", then the default filter is :py:data:`Resampling.NEAREST`. Otherwise, the default filter is :py:data:`Resampling.BICUBIC`. See: :ref:`concept-filters`. :param box: An optional 4-tuple of floats providing the source image region to be scaled. The values must be within (0, 0, width, height) rectangle. If omitted or None, the entire source is used. :param reducing_gap: Apply optimization by resizing the image in two steps. First, reducing the image by integer times using :py:meth:`~PIL.Image.Image.reduce`. Second, resizing using regular resampling. The last step changes size no less than by ``reducing_gap`` times. ``reducing_gap`` may be None (no first step is performed) or should be greater than 1.0. The bigger ``reducing_gap``, the closer the result to the fair resampling. The smaller ``reducing_gap``, the faster resizing. With ``reducing_gap`` greater or equal to 3.0, the result is indistinguishable from fair resampling in most cases. The default value is None (no optimization). :returns: An :py:class:`~PIL.Image.Image` object. """ if resample is None: type_special = ";" in self.mode resample = Resampling.NEAREST if type_special else Resampling.BICUBIC elif resample not in ( Resampling.NEAREST, Resampling.BILINEAR, Resampling.BICUBIC, Resampling.LANCZOS, Resampling.BOX, Resampling.HAMMING, ):但没有指定 resample 的时候，并且 mode 不含 ; 的时候, 就是用 BICUBIC， BICUBIC 是 三次样条插值