simple routine to scan a directory and delete files that aren't valid image types

checkimages.py

import imghdr
import os

#this script will scan every file in a directory and delete any that are not a valid image type that imghdr recognizes.
#see https://docs.python.org/3.1/library/imghdr.html

# 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 or Exif formats
# 'bmp'	BMP files
# 'png'	Portable Network Graphics

def checkimgages(directory):
    list_of_files = os.listdir(directory)
    for ff in list_of_files:
        thepath = os.path.join(directory, ff)
        filetype = imghdr.what(thepath)
        print('\n{} is filetype {}'.format(thepath, filetype))

        if filetype is None:
            print('{} is not a valid filetype. Deleting file'.format(thepath))
            os.remove(thepath)


testdir = 'testdir'
checkimgages(testdir)