Marjaliisa Pitkäranta (1941-2003) was a prolific Finnish artist and illustrator and her works include about 2000 postcards. The one above of a Finnish post office, had this lovely stmap on it.
Another I found on a different card would have been appropriate too:
And while I was on a roll, I also found one from the Netherlands and another from the Czech Republic:
The text on the Czech card translates (according to Google) as, "Get your own stamps".
This is a post for Sunday Stamps, now hosted by Violet Sky at "See it on a Postcard!"