Fotografija je dokazala da je vrč napuknuo.

A very literal breakdown is:

• Fotografija = photograph / photo
• je dokazala = proved
• da = that
• je vrč napuknuo = the jug cracked / the jug had cracked / the jug was cracked depending on context

So the structure is:

• main clause: Fotografija je dokazala = The photograph proved
• subordinate clause: da je vrč napuknuo = that the jug had cracked

Croatian often uses one tense form where English may choose between several past forms.

Because there are two clauses, and each clause has its own verb phrase:

1. Fotografija je dokazala
2. da je vrč napuknuo

In both clauses, je is the 3rd person singular present of biti (to be), used here as an auxiliary to form the perfect tense.

So:

• je dokazala = proved
• je napuknuo = cracked / had cracked

English does not always show this with a separate auxiliary in the same way, but Croatian does.

Because dokazala agrees with fotografija, and fotografija is a feminine singular noun.

In Croatian past tense, the l-participle agrees with the subject in:

• gender
• number

So with fotografija:

• masculine: dokazao
• feminine: dokazala
• neuter: dokazalo

Since fotografija is feminine, the sentence needs dokazala.

Because napuknuo agrees with vrč, and vrč is masculine singular.

Just like dokazala agrees with fotografija, napuknuo agrees with vrč.

Compare:

• vrč je napuknuo = the jug cracked
• čaša je napuknula = the glass cracked
• staklo je napuknulo = the glass pane cracked

So the ending tells you about the subject’s gender and number.

Not exactly.

• napuknuti usually means to crack, to develop a crack, often partially
• puknuti is more general and can mean to crack, burst, snap, break

So vrč je napuknuo suggests the jug got a crack or became cracked, not necessarily that it shattered completely.

That makes napuknuo a good choice if the damage is visible but not total.

Vrč is in the nominative singular because it is the subject of the subordinate clause:

• da je vrč napuknuo

The thing doing the verb action here is vrč: the jug is the thing that cracked.

So:

• Fotografija = nominative subject of the main clause
• vrč = nominative subject of the subordinate clause

There is no direct object here after dokazala; instead, the verb is followed by a content clause introduced by da.

Because je is a clitic, and Croatian clitics normally go in the second position of their clause.

So:

• independent clause: Vrč je napuknuo.
• after da: da je vrč napuknuo

This is the normal, neutral order in standard Croatian.

So da vrč je napuknuo sounds wrong or at least nonstandard in ordinary usage.

Da introduces a subordinate clause meaning that:

• Fotografija je dokazala da...
• The photograph proved that...

After verbs like:

• reći = to say
• znati = to know
• misliti = to think
• dokazati = to prove

Croatian normally uses da before a full clause.

So here it is doing the same job as English that.

Usually no in this kind of sentence.

In English, you can say:

• The photograph proved that the jug had cracked
• The photograph proved the jug had cracked

But in Croatian, with this structure, da is normally required:

• Fotografija je dokazala da je vrč napuknuo.

Leaving it out would sound unnatural or ungrammatical.

Croatian has no articles like English a/an/the.

So:

• fotografija can mean a photograph or the photograph
• vrč can mean a jug or the jug

Context tells you which one is meant.

In this sentence, English might naturally translate it with the, but Croatian does not need a separate word for that.

Formally, it is the Croatian perfect tense.

Depending on context, English may translate it in different ways:

• proved
• has proved
• sometimes even had proved

The same is true for je napuknuo:

• cracked
• has cracked
• had cracked

In a sentence like this, English often prefers had cracked in the subordinate clause, but Croatian simply uses its normal past form.

So do not expect a one-to-one match with English tense names.

Yes, dokazati is perfective.

That means it focuses on the completed result: the proving was achieved.

So:

• Fotografija je dokazala... = the photograph proved it, successfully established it

If you used the imperfective verb dokazivati, you would get something like:

• Fotografija je dokazivala...

That would suggest an ongoing, repeated, or process-like meaning, such as was proving or used to prove, which is not the normal choice here.

So dokazala is the natural form because the sentence is about a completed conclusion.

Here it is a verb form, part of the past tense:

• je napuknuo

This means something like:

• cracked
• became cracked
• had cracked

It describes an event/change.

If you wanted to describe the jug as being in a cracked state, Croatian could use an adjective such as napuknut in a different structure. But this sentence is talking about the event of the jug’s cracking, not just its condition.

Vrč is tricky for English speakers because it has no written vowel between v and r.

A rough guide:

• č sounds like ch in church
• the r is syllabic, so the whole word is basically one syllable: vrč

A rough approximation is vrch, though English speakers often insert a tiny vowel by habit.

So try something close to:

• vrch

with a rolled or tapped r if possible.