[Originally posted by yschools414 on 2008-03-31 00:46:51-07]
I am changing a single tag (UserComment) in a JPEG file and then saving it to a new file. I notice that the new file and the old file differ in both the PreviewImage and ThumbnailImage. Why would this happen if I only changed the UserComment tag?
[Originally posted by exiftool on 2008-03-31 11:11:23-07]
The preview and thumbnail images themselves should be the same after
editing, however the locations in which they are stored in the file
may change, but this is not significant. The PreviewImageStart and
ThumbnailImageOffset tags just give the positions of these images
in the file. I hope this makes sense.
- Phil