add thumbnailimages to JPG file

[lupo]

Hi,

I am trying to add multiple preview/thumbnail images to a JPEG file. I have already tried to add a thumbnail which worked fine. But then adding a previewimage failed. Trying to add another thumbnailimageis just replacing the previous or throws errors.

exiftool.exe "-thumbnailimage<=thumb72px.jpg" image2000px.jpg (works)
exiftool.exe "-previewimage <=thumb288px.jpg" image2000px.jpg (does nothing)
exiftool.exe "-thumbnailimage<=thumb288px.jpg" image2000px.jpg (replaces thumb72px)
exiftool.exe "-thumbnailimage+<=thumb288px.jpg" image2000px.jpg (Warning: Shift value for Olympus:ThumbnailImage is not a number)

Is it possible to add rather than replace thumbnails?

Thanks in advance

[Phil Harvey]

The preview image is not part of the EXIF standard, so ExifTool can not be used to create this tag.  It will only write PreviewImage if it already exists in a file (in the proprietary maker notes).

The EXIF standard specifies only a single thumbnail image.  So if you try to write another one, the first will be replaced.

- Phil