2003.10.01 12:27 "[Tiff] Reading thumbnail", by email@example.com
By reading TIFF Specification, full-size image is in IFD0 and thumbnail is in IFD1.
No, not really. Sometimes a thumbnail gets stored as a second image in the TIFF file. Sometimes there is no thumbnail. Sometimes there is a second image, but it's not a thumbnail version of the first image.
So I'd be careful making assumptions about what you can find in a TIFF file.
Thank you for your advice!!
I confused TIFF with EXIF.
at last, I could get thumbnail data created by Photoshop.
1. I modified libtiff to get the value of tag 34377.
2. I read ID 1033 and 1036 in the data.
more detail, http://partners.adobe.com/asn/developer/pdfs/tn/PhotoshopFileFormats.pdf