Question to PreviewImage

[herb]

Hello Phil,

the *.jpg images taken with my Olympus E-PL6 camera have an embedded thumbnailImage and also an embedded previewImage.

Testing my application I performed some tests with these embedded images:
- Both embedded images can be extracted into an external file and also both can be deleted.
- I am able to copy the thumbnailImage back into the image, after I have deleted it.

But I have a problem to restore the previewImage:
Both commands do not work
exiftool -tagsfromfile <image>.jpg_original -previewimage <image>.jpg
exiftool -previewimage<=<extractedpreview>.jpg <image>jpg

The response is always: 0 image file updated - 1 image files unchanged

What do I wrong?

Thanks for your help in advance
Best regards
Herb

[Phil Harvey]

Hi Herb,

Preview images are really problematic.  ExifTool can't write many of them.  I don't have time right now to test E-PL6 JPEG files specifically, but it doesn't surprise me if this doesn't work.

- Phil

[herb]

Hello Phil,

thanks for your answer.
I thought a previewImage is always strored as a kind of trailer after the image itself (atleast for jpg images) and have not seen problems.

But your answer sounds that is is
- in principal not possible to store a previewImage inside a *.jpg image ( and also RAW images)
- except in rare cases (which have to be found by try and error)

Best regards
Herb

[Phil Harvey]

Hi Herb,

There are at least a dozen different ways in which preview images are stored.  Many times it is as a trailer, but then there is also usually a pointer somewhere in the maker notes or elsewhere that needs to be set to point at the image.

- Phil