How can I get the thumbnail that nautilus uses for a given file?

Question

Nautilus shows me a thumbnail of a file, if its an image it will show me a preview, if its a video it will show a frame from the video, if its a document it will show me the application icon.

How can I access the image?

I see they are cached in ~/.thumbnail/ however they are all given unique names.

Answer 1

the thumbnail filename is an md5 of the filename. However the filename is the absolute URI to the image (without a newline).

So you need to do:

echo -n 'file:///home/yuzem/pics/foo.jpg' | md5sum

And if it has spaces, you need to convert them to '%20', ex for "foo bar.jpg"

echo -n 'file:///home/yuzem/pics/foo%20bar.jpg' | md5sum

Found at Ubuntu forums. See also the Thumbnail Managing Standard document, linked from the freedesktop.org wiki.

Answer 2

Simple Python tool to calculate the thumbnail path. Written by Raja, shared as an ActiveState code recipe. Note, however, that this code does not escape filenames with spaces or special characters; which means this code does not work for all filenames.

"""Get the thumbnail stored on the system.
Should work on any linux system following the desktop standards"""

import hashlib
import os

def get_thumbnailfile(filename):
    """Given the filename for an image, return the path to the thumbnail file.
    Returns None if there is no thumbnail file.
    """
    # Generate the md5 hash of the file uri
    file_hash = hashlib.md5('file://'+filename).hexdigest()

    # the thumbnail file is stored in the ~/.thumbnails/normal folder
    # it is a png file and name is the md5 hash calculated earlier
    tb_filename = os.path.join(os.path.expanduser('~/.thumbnails/normal'),
                               file_hash) + '.png'

    if os.path.exists(tb_filename):
        return tb_filename
    else:
        return None

if __name__ == '__main__':
    import sys
    if len(sys.argv) < 2:
        print('Usage:  get_thumbnail.py filename')
        sys.exit(0)

    filename = sys.argv[1]
    tb_filename = get_thumbnailfile(filename)

    if tb_filename:
        print('Thumbnail for file %s is located at %s' %(filename, tb_filename))
    else:
        print('No thumbnail found')