ExifTool Forum

ExifTool => Bug Reports / Feature Requests => Topic started by: herb on October 03, 2022, 06:44:46 AM

Title: Questions to delete PreviewImage
Post by: herb on October 03, 2022, 06:44:46 AM
Hello Phil,

I am working with ExifTool 12.46 on my Windows 10 system.

I usually work with *.jpg images created by an Olympus camera.
So these images have a ThumbnailImage and also a PreviewImage.

After deleting the PreviewImage (and only this) I get for -validate the following warning:
Warning: [minor] MakerNotes:PreviewImageLength is zero

This shows that ExifTool has properly updated this MakerNotes tag.

But my question is: can the warning be avoided, because the PreviewImage has been removed properly.
Thanks in advance

Best regards
herb
Title: Re: Questions to delete PreviewImage
Post by: Phil Harvey on October 03, 2022, 07:05:33 AM
Hi Herb,

The preview is likely in the maker notes.  From the exiftool documentation:

            2) In general, MakerNotes tags are considered "Permanent", and may
            be edited but not created or deleted individually.  This avoids
            many potential problems, including the inevitable compatibility
            problems with OEM software which may be very inflexible about the
            information it expects to find in the maker notes.

So when you try to delete this, ExifTool just edits it to write a preview of 0 length to avoid causing problems in the maker notes.

- Phil
Title: Re: Questions to delete PreviewImage
Post by: herb on October 03, 2022, 07:21:27 AM
Hello Phil,

thanks for your reply
But I think we have a misunderstanding.

After deleting/removing the PreviewImage
- value zero for MakerNotes:PreviewImageLength is OK

As far as I know, the PreviewImage is part of the trailer.
So it would be fine when the warning message is suppressed (if possible).

Best regards
herb
Title: Re: Questions to delete PreviewImage
Post by: Phil Harvey on October 03, 2022, 07:55:46 AM
I see.  Suppressing that warning would be ugly, and I don't think it would be worth patching the code for this.

- Phil
Title: Re: Questions to delete PreviewImage
Post by: herb on October 03, 2022, 08:22:07 AM
Hello Phil,

yes I see/understand. It is ok for me.

Thanks for your comments.
Best regards
herb