Bugs : Truncated PreviewIFD directory. IFD dropped. & Bad PreviewIFD directory

[ArtNonoBstant]

Hello people.

First thing, I am french, so please, be indulgente with my english. If you know french expert of exiftool, please give me
Second thing : I want to congratulate Phil Harvey for this tool. I have a lot of questions, but it will be in other topic.

1) My system : Linux, ubuntu 10.10 with Linux 2.6.35-24-generic

2) The version of exiftool : 8.43

3) The specific command line :
exiftool -r -P -TAG=Something *

The exiftool output is the same whatever the TAG using

4) The console output from the command :

Code Select Expand

Warning: Truncated PreviewIFD directory. IFD dropped. - Repas Palestinien/_DSC0062.jpg
Error: [minor] Bad PreviewIFD directory - Repas Palestinien/_DSC0062.jpg

I found, with google, some information about this 2 bugs, but nothing to help me.

In fact I want to know what are this "minor" error & Warning.
Does it mean exifs are corrupted ? Is it serious doctor?
Is there possibilty to fix it (not just using the option wich hide minor error) ?

Thank for help !

[Phil Harvey]

This is a very common problem that is caused by editing Nikon images with image editors which don't properly handle the PreviewIFD in the maker notes.  Luckily, the PreviewIFD only carries the preview image, so only this is lost if the PreviewIFD is deleted.  Using the -m option when writing with ExifTool will do this.

- Phil

[ArtNonoBstant]

Thank Phil

So I can't do preview file with this photo using this command :
exiftool -q -b XXX.jpg -PreviewImage -w "%f - preview.jpg"
Output is, even with the -m option :

Code Select Expand

Warning: Bad PreviewIFD directory - XXX.jpg

Is there how to repair the PreviewIFD, because using preview file on web site is better (perhaps there is other  way with PHP, I don't learn that yet) ?
Is it a random problem or is there way to prevent that issue ? During the copy from the SD card ?

Thank U

[Phil Harvey]

This problem can occur if you use some software to download your images from the SD card, but it shouldn't happen in a direct copy.  What model of camera is this?  It may be difficult to recover the PreviewImage when it the PreviewIFD is damaged.

- Phil