:mod:imghdr --- Determine the type of an image

.. module:: imghdr :synopsis: Determine the type of image contained in a file or byte stream.

Source code: :source:Lib/imghdr.py

---

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

The :mod:imghdr module defines the following function:

.. function:: what(filename, h=None)

Tests the image data contained in the file named by filename, and returns a string describing the image type. If optional h is provided, the filename is ignored and h is assumed to contain the byte stream to test.

.. versionchanged:: 3.6 Accepts a :term:path-like object.

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

+------------+-----------------------------------+ | Value | Image format | +============+===================================+ | 'rgb' | SGI ImgLib Files | +------------+-----------------------------------+ | 'gif' | GIF 87a and 89a Files | +------------+-----------------------------------+ | 'pbm' | Portable Bitmap Files | +------------+-----------------------------------+ | 'pgm' | Portable Graymap Files | +------------+-----------------------------------+ | 'ppm' | Portable Pixmap Files | +------------+-----------------------------------+ | 'tiff' | TIFF Files | +------------+-----------------------------------+ | 'rast' | Sun Raster Files | +------------+-----------------------------------+ | 'xbm' | X Bitmap Files | +------------+-----------------------------------+ | 'jpeg' | JPEG data in JFIF or Exif formats | +------------+-----------------------------------+ | 'bmp' | BMP files | +------------+-----------------------------------+ | 'png' | Portable Network Graphics | +------------+-----------------------------------+ | 'webp' | WebP files | +------------+-----------------------------------+ | 'exr' | OpenEXR Files | +------------+-----------------------------------+

.. versionadded:: 3.5 The exr and webp formats were added.

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

.. data:: tests

A list of functions performing the individual tests. Each function takes two arguments: the byte-stream and an open file-like object. When :func: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.

Example::

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