Pysäköintilupa ei ollut vanhentunut, kun pysäköinninvalvoja otti valokuvan ajoneuvosta.

Because the sentence is looking back from one past moment to an earlier state.

• kun pysäköinninvalvoja otti valokuvan sets a past reference point: the moment when the parking inspector took the photo.
• ei ollut vanhentunut means the permit had not expired by that moment.

So this is the Finnish equivalent of an English past perfect idea.

Compare:

• Lupa ei vanhentunut = the permit did not expire
• Lupa ei ollut vanhentunut = the permit had not expired

The version in your sentence is about the permit’s status at the time the photo was taken, not just about whether expiration happened or not.

Vanhentunut is the active past participle of the verb vanhentua, which means to expire, to become outdated, or to become obsolete.

In this sentence, it is used with olla to form a compound tense:

• on vanhentunut = has expired
• oli vanhentunut = had expired
• ei ollut vanhentunut = had not expired

So vanhentunut is the part that carries the main meaning expired.

Finnish negation works very differently from English.

Finnish uses a special negative verb:

• en, et, ei, emme, ette, eivät

Here the subject is third person singular, so the negative verb is ei.

That negative verb comes before the main verb structure:

• on → ei ole
• oli → ei ollut

So ei ollut vanhentunut is the normal Finnish way to say had not expired.
A form like oli ei is not how Finnish negation is built.

Because Finnish writes compound nouns as one word.

So:

• pysäköinninvalvoja = parking inspector / parking enforcement officer
• literally, something like parking-supervisor

This is very normal in Finnish. English often writes these as two words, but Finnish usually joins them.

Other examples:

• autokauppa = car shop / car dealership
• koulukirja = school book
• kahvikuppi = coffee cup

The first part is pysäköinnin, which is the genitive form of pysäköinti meaning parking.

So the structure is:

• pysäköinnin = of parking
• valvoja = supervisor / monitor / inspector

Together:

• pysäköinninvalvoja = supervisor of parking, so parking inspector

This is a common compound pattern in Finnish: the first part can appear in a genitive form inside the compound.

Good question. Finnish compounds are not all built in exactly the same way.

Here you have two different compound patterns:

• pysäköintilupa = parking permit
  
  • built with a compound stem form
• pysäköinninvalvoja = parking inspector
  
  • built with a genitive first element

So even though both are related to pysäköinti, the first part does not always look the same inside compounds.

This is very common in Finnish, and often the best approach is to learn the whole compound as a vocabulary item.

Because valokuvan is the object form used here.

With a completed action in an affirmative sentence, Finnish often uses the total object. In the singular, that often looks like an -n form.

So:

• otti valokuvan = took a photograph

The idea is that the action is complete: one whole photo was taken.

A useful comparison:

• Hän otti valokuvan. = He or she took a photo.
• Hän ei ottanut valokuvaa. = He or she did not take a photo.

Notice how negation often changes the object to the partitive, here valokuvaa.

Because Finnish says ottaa valokuva jostakin, literally to take a photo from/of something.

So:

• ajoneuvo = vehicle
• ajoneuvosta = of the vehicle / from the vehicle

In English we usually say a photo of the vehicle, but Finnish uses the elative ending -sta/-stä in this expression.

Compare:

• valokuva talosta = a photo of the house
• valokuva koirasta = a photo of the dog
• otti valokuvan ajoneuvosta = took a photo of the vehicle

So ajoneuvosta is not the main object here. The object is valokuvan.
Ajoneuvosta tells what the photo was of.

The dictionary form is ottaa, meaning to take.

In the past tense, ottaa becomes:

• otti = took

So:

• ottaa valokuva = to take a photo
• otti valokuvan = took a photo

This is a very common verb, and its past form is worth memorizing.

Here kun means when.

It introduces a subordinate clause that gives the time of the main clause:

• Pysäköintilupa ei ollut vanhentunut = the parking permit had not expired
• kun pysäköinninvalvoja otti valokuvan ajoneuvosta = when the parking inspector took a photo of the vehicle

So the whole sentence means that at the time of the photo, the permit had not expired.

It means the permit was not expired at that moment.

In many real situations, that strongly suggests it was still valid in terms of date. But strictly speaking, the sentence only tells you one thing:

• it had not expired yet when the photo was taken

It does not tell you anything else about possible problems with the permit.

No. It only tells you the permit had not expired by the time the photo was taken.

What happened afterward is not stated.

So the sentence leaves these possibilities open:

• it expired later
• it never expired during the relevant period
• we simply do not know

Finnish has no articles like a and the.

So Finnish does not mark that distinction directly in the way English does. You choose the English article from context.

In this sentence, English will often use the because the situation sounds specific:

• the parking permit
• the parking inspector
• the vehicle

But Finnish itself does not have separate words for a and the.

Yes. Finnish allows that.

You could also say:

• Kun pysäköinninvalvoja otti valokuvan ajoneuvosta, pysäköintilupa ei ollut vanhentunut.

That means the same thing.

The difference is mostly about style and information flow:

• starting with Pysäköintilupa... puts the permit first
• starting with Kun pysäköinninvalvoja... puts the time-setting clause first

Both are natural Finnish.