Preserve exif data of image with PIL when resize(create thumbnail)

Question

When I try to resize (thumbnail) an image using PIL, the exif data is lost.

What do I have to do preserve exif data in the thumbnail image? When I searched for the same, got some links but none seem to be working.

from PIL import  Image
import StringIO

file_path = '/home/me/img/a.JPG'
im = Image.open( file_path)
THUMB_SIZES = [(512, 512)]
for thumbnail_size in THUMB_SIZES:
    im.thumbnail( thumbnail_size, Image.ANTIALIAS)
    thumbnail_buf_string = StringIO.StringIO()
    im.save('512_' + "a", "JPEG")

The orginal image has exif data, but image im(512_a.JPEG) doesn't.

Answer 1

I read throught some of the source code and found a way to make sure that the exif data is saved with the thumbnail.

When you open a jpg file in PIL, the Image object has an info attribute which is a dictionary. One of the keys is called exif and it has a value which is a byte string - the raw exif data from the image. You can pass this byte string to the save method and it should write the exif data to the new jpg file:

from PIL import Image

size = (512, 512)

im = Image.open('P4072956.jpg')
im.thumbnail(size, Image.ANTIALIAS)
exif = im.info['exif']
im.save('P4072956_thumb.jpg', exif=exif)

To get a human-readable version of the exif data you can do the following:

from PIL import Image
from PIL.ExifTags import TAGS

im = Image.open('P4072956.jpg')
for k, v in im._getexif().items():
    print TAGS.get(k, k), v

Answer 2

In my project, i met the same issue with you. After searching Google, I found piexif library. It help to Pilow save exif data to thumbnails.

You can use the source code below:

from PIL import  Image
import piexif
import StringIO


file_path = '/home/me/img/a.JPG'
im = Image.open( file_path)

# load exif data
exif_dict = piexif.load(im.info["exif"])
exif_bytes = piexif.dump(exif_dict)

THUMB_SIZES = [(512, 512)]
for thumbnail_size in THUMB_SIZES:
    im.thumbnail( thumbnail_size, Image.ANTIALIAS)
    thumbnail_buf_string = StringIO.StringIO()
    # save thumbnail with exif data
    im.save('512_' + "a", "JPEG", exif=exif_bytes)

Note: I am using python 3.4 and ubuntu 14.04

Answer 3

import pyexiv2
from PIL import  Image

file_path = '/home/../img/a.JPG'
metadata = pyexiv2.ImageMetadata(file_path)
metadata.read()
thumb = metadata.exif_thumbnail
thumb.set_from_file(file_path)
thumb.write_to_file('512_' + "a")
thumb.erase()
metadata.write()

Now I open the image using (Patch Image Inspector) , I can see the exif data