Version:            (using KDE KDE 3.5.7)
Installed from:    Compiled From Sources
OS:                Linux

exiv2 is able to write geodata metadata into e.g png files.
Its easy to tests this: Take a jpeg, add geo-data with the kipi-plugin, open in digikams image editor and save as png. You will see, the geo-data are part of the png metadata.

But you can not add these geo-tag direct into a png, as you can find code like this in this plugin:

[...]
// We only add all JPEG files as R/W because Exiv2 can't yet 
// update metadata on others file formats. 
   QFileInfo fi(url.path()); 
   QString ext = fi.extension(false).upper(); 
   bool ret = false; 
   if (ext == QString("JPG") || ext == QString("JPEG") || ext == QString("JPE")) 
   {
[...] 

So, the comment in the source code is definitely wrong and to test the file format a simple extention is used. What about kde standard test to check a filetype based on MIME data?

KMimeType::Ptr type = KMimeType::findByURL("/home/bernd/foobar.jpg");
vs
KMimeMagicResult *result = KMimeMagic::self()->findFileType("/home/bernd/foobar.jpg");

(from: http://developer.kde.org/documentation/library/kdeqt/kde3arch/mime.html )

Bye

  Thorsten