[Digikam-users] Storing comments and tags outside the image?

[Paul Waldo]

On Wednesday 22 November 2006 4:07 am, Gilles Caulier wrote:
> On Friday 17 November 2006 18:15, Paul Waldo wrote:
> > I consider my images as digital
> > negatives and don't want them touched once uploaded to the computer.
>
> Let's me explain an important point about metadata : image data (the
> picture that you can see in screen) are not meta-data and vis-versa.
>
> Both data are stored in separate sections in picture files. This is want
> mean than metadata can be changed without touch something in image data.
>
> Gilles

This is true conceptually, but very different from a practical perspective.  I 
understand that any modification to the data portion of the file *should not* 
affect the image.  I can think of at least two situations where this may not 
hold, though:

- The metadata software has a bug that causes it to write the metadata in some 
strange way.  You now have weird stuff in the file, which may overwrite the 
image data.

- There is a disk IO problem.  Lets say that I am very low on disk space and 
the number of characters in my brand new comment pushes the file size over 
the limit, causing a disk-full error.  The image may be in a strange state.

Digikam may handle situation 2 very well, but situation 1 seems out of its 
control.  I would love to be able to take advantage of writing meta data 
directly to the file, but it scares me.  I'd hate for my 
undeniable-proof-of-Sasquatch photo to get corrupted because of a bug in 
exiv2 (for example).  That's why I wanted to make sure that the original 
image *file* does not get touched.

Paul