Author Topic: View EXIF thumbnail  (Read 17655 times)

Gawi

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View EXIF thumbnail
« on: December 11, 2010, 07:47:21 PM »
Hello,
Is there a way in Exiftool GUI to see the embedded EXIF Thumbnail?

Digital cameras embed thumbnails in the pictures, and later, if you edit these pictures with an image editor it sometimes fail to update the embedded thumbnail. This can cause privacy issues. Say for example you blur a license plate or some other information in the picture it can still maybe be seen in the embedded thumbnail.

I first thought the thumbnail in the lower left was the exif thumbnail but it seems to just be a smaller version of the full image.

Is there a way in the program to see the real thumbnail, and if not is it something that can be included in a future version (assuming exiftool can extract that thumbnail) ?

Also, when doing a lossless rotate from the program, is the exif thumbnail rotated as well?

BogdanH

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Re: View EXIF thumbnail
« Reply #1 on: December 12, 2010, 06:03:31 AM »
Hi,

No, you can't see "real" thumbnail image inside GUI. What you see in GUI is (as you have figured out) image parsed by Windows and then rendered/resized in GUI. This is quite common approach, because it makes variable sized "thumbnails" possible -real thumbnails are quite small, though.

Ok, what you can do is:

1. I don't know if it's defined by standard, but (to my knowledge) thumbnail image always resides inside Exif:IFD1 section of jpg file. Thus, you can simply delete this section (GUI menu: Remove metadata) -it never happened to me, that some software would require real thumbnail to be present.

2. You can manually (not inside GUI) extract actual thumbnail by using command:
exiftool -b -ThumbnailImage MyPhoto.jpg>MyThumb.jpg
Now, after you have edited thumbnail, you can embed it back to original file:
exiftool "-ThumbnailImage<=MyThumb" MyPhoto.jpg

Yes, lossless rotation rotates thumbnail as well -related to this: be aware, that actual thumbnail orientation must match main image orientation (bacause Orientation tag is ment for both: main image and thumbnail image).

Bogdan

Gawi

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Re: View EXIF thumbnail
« Reply #2 on: December 12, 2010, 09:10:02 AM »
Hi, thanks for the clarification.

Well, consider it a wish for a new feature - the more jpg-metadata you can see the better imo. Maybe a new "Exif thumbnail" button in the right pane, a menu item, or somewhere else in GUI where you can see the whole embedded thumbnail.

You're right, they seem to be quite small, I think thumbnails in pictures from my camera where around 160x120.

Thanks.

Gawi

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Re: View EXIF thumbnail
« Reply #3 on: December 12, 2010, 10:08:59 AM »
Also, so called preview images, is that a separate concept from thumbnails? Is that for RAW images or something written by every camera even in jpg-files?

Phil Harvey

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Re: View EXIF thumbnail
« Reply #4 on: December 12, 2010, 11:04:30 AM »
Previews are written by many cameras in JPEG images too.
...where DIR is the name of a directory/folder containing the images.  On Mac/Linux, use single quotes (') instead of double quotes (") around arguments containing a dollar sign ($).

BogdanH

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Re: View EXIF thumbnail
« Reply #5 on: December 12, 2010, 12:02:31 PM »
I could make some menu in GUI for extract/embed thumbnail... but I believe, must average users don't bother with "real" thumbnails at all -because, as said, they aren't much used in today's software. And as you see, for special cases (security reasons, etc.), there's quite simple command line to be executed.
That leads to making preview of "real" thumbnail inside GUI.. would require quite some work.. and considering "nobody" uses them.. sorry to dissapoint you.

Yes, beside actual raw image data, raw image files may contain one (or more) jpg files. So, for example, Canon raw files contain preview jpg image and thumbnail jpg image. Of course, preview jpg is what we see on screens.

Bogdan

chameleon

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Re: View EXIF thumbnail
« Reply #6 on: July 26, 2018, 05:44:51 AM »
Run this command:

Code: [Select]
exiftool -a -b -W %d%f_%t%-c.%s -preview:all YourFileOrDirectory
Example command output:

Code: [Select]
Warning: Invalid EXIF text encoding for UserComment - 20180709_141902_HDR.jpg
Warning: [minor] Unrecognized MakerNotes - 20180709_141902_HDR.jpg
    1 output files created

There will be generated the file 20180709_141902_HDR_ThumbnailImage.jpg