ExifThumb

[telenkor]

I tried to extract the preview based on the code from here.

file = "/Volumes/0001.NEF"
image = exiv2.ImageFactory.open(file)
image.readMetadata()
exifData = image.exifData()

thumb = exiv2.ExifThumb(exifData)
print('Thumbnail type:', thumb.mimeType())
data = thumb.copy()
thumb_im = PIL.Image.open(io.BytesIO(data.data()))

It doesn’t get to the opening in PIL because thumb.mimeType() is "", data — 0 bytes.

[jim-easterbrook]

Your NEF file probably doesn't have a thumbnail. Most raw formats use "preview" images (at various sizes) instead. The libexiv2 PreviewManager class handles those. Here's how I do it in one of my applications: https://github.com/jim-easterbrook/Photini/blob/main/src/photini/exiv2.py#L482

[jim-easterbrook]

Just for interest - I may have fixed my problem with Canon maker notes being truncated in exiv2 v0.28 (Exiv2/exiv2#2860) so the next release of python-exiv2 might be using v0.28.2.

[telenkor]

Cool news. I'll keep an eye on the updates. As soon as it comes out, I will be glad to experiment with this version in my project.

[jim-easterbrook]

It depends when exiv2 do their next release. Python-exiv2 v0.16.0 is almost ready for release and I don't want to delay it too long. (You can see what's changed by looking at the v0.16.0 branch on GitHub.)

[jim-easterbrook]

I've just released python-exiv2 v0.16.0 (with libexiv2 0.28.1) and python-exiv2 v0.16.1 (with libexiv2 0.27.7). This means that a simple "install latest" will still be on the older libexiv2, but you can try the newer libexiv2 with an explicit pip install --user exiv2==0.16.0.

[telenkor]

Great news for the New Year! I tried the version with the 0.28.x library. Everything is fine. My patch that corrected the header of Webp images is no longer needed.
For users of the virtual environment (PyCharm), install version 16.0 with the following command: pip install exiv2==0.16.0