1:mod:`imghdr` --- Determine the type of an image 2================================================ 3 4.. module:: imghdr 5 :synopsis: Determine the type of image contained in a file or byte stream. 6 7**Source code:** :source:`Lib/imghdr.py` 8 9-------------- 10 11The :mod:`imghdr` module determines the type of image contained in a file or 12byte stream. 13 14The :mod:`imghdr` module defines the following function: 15 16 17.. function:: what(filename[, h]) 18 19 Tests the image data contained in the file named by *filename*, and returns a 20 string describing the image type. If optional *h* is provided, the *filename* 21 is ignored and *h* is assumed to contain the byte stream to test. 22 23The following image types are recognized, as listed below with the return value 24from :func:`what`: 25 26+------------+-----------------------------------+ 27| Value | Image format | 28+============+===================================+ 29| ``'rgb'`` | SGI ImgLib Files | 30+------------+-----------------------------------+ 31| ``'gif'`` | GIF 87a and 89a Files | 32+------------+-----------------------------------+ 33| ``'pbm'`` | Portable Bitmap Files | 34+------------+-----------------------------------+ 35| ``'pgm'`` | Portable Graymap Files | 36+------------+-----------------------------------+ 37| ``'ppm'`` | Portable Pixmap Files | 38+------------+-----------------------------------+ 39| ``'tiff'`` | TIFF Files | 40+------------+-----------------------------------+ 41| ``'rast'`` | Sun Raster Files | 42+------------+-----------------------------------+ 43| ``'xbm'`` | X Bitmap Files | 44+------------+-----------------------------------+ 45| ``'jpeg'`` | JPEG data in JFIF or Exif formats | 46+------------+-----------------------------------+ 47| ``'bmp'`` | BMP files | 48+------------+-----------------------------------+ 49| ``'png'`` | Portable Network Graphics | 50+------------+-----------------------------------+ 51 52.. versionadded:: 2.5 53 Exif detection. 54 55You can extend the list of file types :mod:`imghdr` can recognize by appending 56to this variable: 57 58 59.. data:: tests 60 61 A list of functions performing the individual tests. Each function takes two 62 arguments: the byte-stream and an open file-like object. When :func:`what` is 63 called with a byte-stream, the file-like object will be ``None``. 64 65 The test function should return a string describing the image type if the test 66 succeeded, or ``None`` if it failed. 67 68Example:: 69 70 >>> import imghdr 71 >>> imghdr.what('bass.gif') 72 'gif' 73 74
