I've occasionally used KPhotoAlbum for a few years and eventually added many tags to the pictures.

But I've decided I wanted to try other tools, and digiKam seems to be the best option from the many reviews I've read.

Still, there's apparently no automatic feature to import into digiKam the tags set in KPhotoAlbum.

Fortunately, some smart people have implemented Perl tools allowing to overcome this issue.

The process involves modifying the pictures to save the tags inside the files, using the IPTC standard. Then, digiKam will be able to load the tags from the modified files.

Here's a copy of the (translated) kphotoalbum2iptc.pl script (the original as in french) I copied from this blog post (in french too).

I've been able to generate .deb packages for the required 2 perl libs dependencies using the method described in the referenced post , with : dh-make-perl  --build --cpan Image::Kimdaba and dh-make-perl  --build --cpan Image::IPTCInfo

Thanks to Pierre Doucet and Bruno Adele for sharing this. Hope this helps.