After having my photo taken at the police office for at least my two latest passports it's somewhat surprising to hear about so many countries still using "the old way". There are such obvious advantages both in security and convenience by having the passport issuer take the photo and the technology is obviously available.
They have a specially kited photo booth, where you also leave two fingerprints for additional biometric verification.
In order to renew your passport you need to schedule an appointment withyour local passport office.
Last time I renewed, 2013, it took 7 weeks until the earliest available appointment, which was a bit surprising. I'm sure, though, there's an emergency shortcut for a price.
The new passport arrives two days later by mail.
> Such manipulation of photos is typically invisible to the human eye, the researchers found.
[1] https://www.poliisi.fi/passport/passport_photo_instructions
https://lupakuvienvastaanotto.fi/Default.aspx
E: not to mention that the page you linked doesn't even say anything about prohibiting self taken photos.