imghdr --- 推測圖片種類


Deprecated since version 3.11, will be removed in version 3.13: imghdr 模組 (module) 即將被棄用(詳情與替代方案見 PEP 594)。

The imghdr module determines the type of image contained in a file or byte stream.

The imghdr module defines the following function:

imghdr.what(file, h=None)

Test the image data contained in the file named file and return a string describing the image type. If h is provided, the file argument is ignored and h is assumed to contain the byte stream to test.

在 3.6 版的變更: Accepts a path-like object.

The following image types are recognized, as listed below with the return value from what():


Image format


SGI ImgLib Files


GIF 87a and 89a Files


Portable Bitmap Files


Portable Graymap Files


Portable Pixmap Files




Sun Raster Files


X Bitmap Files


JPEG data in JFIF or Exif formats


BMP 檔案


Portable Network Graphics


WebP 檔案


OpenEXR 檔案

在 3.5 版被加入: 新增 exrwebp 格式。

You can extend the list of file types imghdr can recognize by appending to this variable:


A list of functions performing the individual tests. Each function takes two arguments: the byte-stream and an open file-like object. When what() is called with a byte-stream, the file-like object will be None.

The test function should return a string describing the image type if the test succeeded, or None if it failed.


>>> import imghdr
>>> imghdr.what('bass.gif')