Seth Price on wrote...
| I did some looking around, and it looks like it's part of the EXIF
| spec. It's discussed in part on these sites:
| http://netzreport.googlepages.com/hidden_data_in_jpeg_files.html
| http://www.hutta.com/thumbs/
| http://www.sno.phy.queensu.ca/~phil/exiftool/writing.html (look under
| "The Preview Image Problem")
|
| It is (of course) discussed in more depth in the documentation:
| http://it.jeita.or.jp/document/publica/standard/exif/english/
| jeida49e.htm
|
| ~Seth
|
More specifically it is dependant on the image format. JPEG TIFF and
EPSI, and probably BMP and others, all include methods to specify a
preview thumbnail of one sort or another.
Many programs however ignore it an generate there own thumbnails though
various means. This includes MAC's, Linux, Gimp, etc. basically as the
normal built in thumbnail is not suitable to there needs of a thumbnail.
(Size, scalability, speed, accuracy etc)...
These bult in thumbnails are also not part of the scope of ImageMagick.
For JPEG look at the special program "jhead".
However while this can 'update' a thumbnail, it will not add a thumbnail
to a image in which the thumbnail has been removed.
Anthony Thyssen ( System Programmer ) <[EMAIL PROTECTED]>
-----------------------------------------------------------------------------
Imagine if every Thursday your shoes exploded if you tied them the
usual way. This happens to us all the time with computers, and
nobody thinks of complaining. -- Jef Raskin
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Anthony's Home is his Castle http://www.cit.gu.edu.au/~anthony/
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