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(python2.1-lib.info)imghdr

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Determine the type of an image
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Determine the type of image contained in a file or byte stream.

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

The `imghdr' module defines the following function:

`what(filename[, h])'
     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.

The following image types are recognized, as listed below with the
return value from `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 format
'bmp'                                BMP files
'png'                                Portable Network Graphics

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

`tests'
     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.

Example:

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