为什么在 Pillow-python 中调整图像大小会删除 Image.format？

Question

我正在使用 Pillow

在 python 中调整图像大小

image = Image.open("image_file.jpg")

print(image.format) # Prints JPEG

resized_image = image.resize([100,200],PIL.Image.ANTIALIAS)

print(resized_image.format) # Prints None!!

为什么 resized_image.format 持有 None 值？

以及如何在使用 pillow 调整大小时保留格式？

Answer 1

因为Image.resize creates a new Image object (resized copy of the image) and for any images when creating by the library itself (via a factory function, or by running a method on an existing image), the "format”属性设置为None.

如果您需要格式属性，您仍然可以这样做：

image = Image.open("image_file.jpg") #old image object
resized_image = image.resize([100,200],PIL.Image.ANTIALIAS)
resized_image.format = image.format # original image extension

Read the docs

Answer 2

如 documentation 中所述：

The file format of the source file. For images created by the library itself (via a factory function, or by running a method on an existing image), this attribute is set to None.

您可以指定保存格式：

image.save(fp, 'JPEG')

Answer 3

您可以使用保存评论保存调整大小的图片

resized_image.save("New_image.png")

它将保存到您的当前目录。

如果你想在 python 控制台中看到你必须运行

resized_image.show()

为什么在 Pillow-python 中调整图像大小会删除 Image.format？

why does resizing image in Pillow-python remove Image.format?

python

python-imaging-library

pillow