Thumbnail image from DNG file is inappropriate using imagemagick or exif tool

Question

I have a DNG image and a cropped monochromatic version of the image. Both are generating the same file as the thumbnail when I run any of the below commands:

magick.exe C:\sample1crop.dng -resize 500x375 C:\crop-T.JPG

or

magick.exe dng:C:\sample1crop.dng -intent relative -sample 500x375> -strip -auto-orient -density 72 C:\crop-T.JPG

or

magick.exe convert dng:C:\sample1original.dng -thumbnail 500x375 -filter -auto-orient -density 72 C:\orig-T.JPG

As I am not allowed to upload the DNG files, thus I uploaded the images in hightail, sharing the link below: https://spaces.hightail.com/space/ThDEDYZVey

The generated thumbnail for both the cases:

I tried to get the thumbnail with exiftool as well:

exiftool -b -PreviewImage C:\86854\SLS\Issues\ART-73712\crop-T.JPG > C:\86854\SLS\Issues\ART-73712\thumbnail.jpg

exiftool -b -ThumbnailImage C:\86854\SLS\Issues\ART-73712\crop-T.JPG > C:\86854\SLS\Issues\ART-73712\thumbnail.jpg

but the resulting file seems corrupted. When I extract the exiftool metadata I see: "ThumbnailTIFF": "(Binary data 42194 bytes, use -b option to extract)"

My requirement here is to get a generic cmd that provides a cropped monochromatic thumbnail similar to the original image.

Answer 1

Using this exiftool command, I was able to extract four images from those files.

You don't mention what OS or shell you're using but if you're using Windows PowerShell, it is known to corrupt binary data when piping or redirecting. Use CMD and you should be able to extract the images properly.