It seems that the pictures from German Federal Archive have been detected by the search engine of Wikimedia Commons. So now you can find more easily pictures that have not been categorized by now. Every picture has an original description in German.
To find pictures from the history of your country, I suggest searching simply by the German name of the country (with "Search", not "Go"). I have tried out some (sometimes adding "Bundesarchiv" to the search), and nearly always I got some pics of politicians from that country visiting Germany, or vice versa, or German soldiers in WWI or II, or a picture of a head of state for a German magazine etc. Or you can search the name of a person; so I could just add a picture to [[nl:Bernhard van Lippe-Biesterfeld]].
Ziko
wikimedia-l@lists.wikimedia.org