Learn Hardcore Croatian: Na mreži imam nekoliko pratitelja koji vole moje fotografije. - On the internet I have several followers who like my photos.

After the preposition na, when you mean location (where something is), Croatian uses the locative case. The locative of mreža is mreži:

nominative: mreža (network)
locative: (na) mreži (on the network)

So na mreži = on the network / online.

If you said na mreža, that would be ungrammatical, because na (with location meaning) needs the locative case, not the nominative.

Why is it nekoliko pratitelja and not nekoliko pratitelji?

The word nekoliko (several, a few) always takes the genitive plural in Croatian.

The noun is pratitelj (a follower):

nominative plural (subject form): pratitelji – followers
genitive plural: pratitelja – of followers

After nekoliko, you must use genitive plural:

nekoliko pratitelja = several followers
nekoliko prijatelja = several friends
nekoliko automobila = several cars

So nekoliko pratitelji is incorrect; it has to be nekoliko pratitelja.

What is the nuance of pratitelj? Is it the same as follower on social media?

Pratitelj most often means follower in a broad sense: someone who follows, tracks, or pays attention to you or to something.

In modern usage:

On social media, pratitelj = follower (Instagram, Twitter/X, etc.).
In other contexts, it can mean companion, attendant, or adherent (someone who follows a movement, school of thought, etc.).

Other related words:

sljedbenik – follower in a more ideological sense (e.g. follower of a religion, ideology)
pretplatnik – subscriber (for paid subscriptions, magazines, services)
Colloquial English loan: follower is sometimes used in Croatian speech, but pratitelj is the standard Croatian word on platforms that localize their UI.

In this sentence, pratitelja is most naturally understood as social media followers.

Why is it koji vole and not koje vole or koji volim?

Koji is a relative pronoun meaning who/that/which. It must agree in gender and number with the noun it refers to.

Here, it refers to pratitelja (followers). Even though pratitelja appears in the genitive plural, the logical noun is pratitelji:

logical form: pratitelji (masculine plural, nominative)
actual form in the sentence (after nekoliko): pratitelja (genitive plural)

Agreement is made with the logical noun (followers, they), so:

koji – nominative masculine plural
vole – 3rd person plural verb form (they like)

So:

koji vole = who like

Koje would be for a feminine plural noun (e.g. djevojke koje vole… – girls who like…), so it doesn’t match pratitelj (masculine).

Volim is I like, 1st person singular, but here the subject of vole is they = the followers, not I.

Why is the verb vole plural? Doesn’t nekoliko sometimes behave like singular?

The agreement can be tricky with quantity words like nekoliko.

In the main clause, speakers sometimes treat nekoliko + genitive as grammatically singular or plural, depending on style and region.
In a relative clause (with koji), Croatian normally treats it as plural, matching the logical they.

Here, in the relative clause:

Subject: (oni) koji = they who
Verb: vole = they like

So koji vole (plural) is the natural choice.

You might see:

Nekoliko ljudi je došlo. – A few people came. (verb often singular)
Nekoliko ljudi koji su došli… – A few people who came… (relative clause, plural verb su došli)

In your sentence, keep vole (plural). Saying koji voli would sound wrong.

Why is it moje fotografije, not mojih fotografija?

The verb voljeti (to like, to love) takes a direct object in the accusative case.

Fotografija (photo) is feminine:

nominative singular: fotografija
accusative plural: fotografije (same form as nominative plural)

So fotografije here is accusative plural: (they) like my photos.

The possessive moj has to agree with fotografije (feminine plural):

moje fotografije = my photos (feminine plural, accusative)

Mojih fotografija would be genitive plural (“of my photos”), which would be used in structures like:

nekoliko mojih fotografija – several of my photos
bez mojih fotografija – without my photos

But after vole, you want the accusative, so moje fotografije is correct.

What form is fotografije here exactly? How do you know it’s accusative?

Fotografije can look ambiguous, because Croatian feminine nouns in -a often have identical forms for nominative plural and accusative plural.

For fotografija:

nominative singular: fotografija
accusative singular: fotografiju
nominative plural: fotografije
accusative plural: fotografije

We decide by function:

After vole (they like), the word is a direct object, so it must be accusative plural, even though it looks the same as the nominative plural.

So, fotografije here = (they like) photos (accusative plural).

Can I change the word order, like Imam nekoliko pratitelja na mreži koji vole moje fotografije? Is that still correct?

Yes, that word order is perfectly correct:

Na mreži imam nekoliko pratitelja koji vole moje fotografije.
Imam nekoliko pratitelja na mreži koji vole moje fotografije.

Both are grammatical and natural.

Subtle nuance:

Na mreži imam… – puts a little emphasis first on online vs. somewhere else.
Imam nekoliko pratitelja na mreži… – starts with I have several followers, and then adds online as extra information.

In everyday conversation, both would be understood the same way.

Why is ja (I) not written before imam? Is it wrong to say Ja na mreži imam…?

In Croatian, subject pronouns (ja, ti, on, etc.) are often omitted, because the verb ending already shows who the subject is.

imam can only be I have (1st person singular), so ja is not needed.

Your original:

Na mreži imam nekoliko pratitelja… is completely normal.

You can add Ja for emphasis or contrast:

Ja na mreži imam nekoliko pratitelja… – I (as opposed to someone else) have a few followers online…

But in neutral, non-contrastive sentences, Croatians usually leave ja out.

Is pratitelj only for people? Could it be for pages or channels like followers in English?

Pratitelj is primarily understood as a person who follows something or someone.

In practice:

pratitelj profila – follower of a profile (a person or a page)
pratitelj kanala – follower/subscriber of a channel
pratitelji on social networks = the users who follow that account

So while the word itself is human-oriented, by extension it refers to the accounts/users that follow any type of profile (personal account, business page, channel, etc.), similar to English followers of a page.

Can I use more colloquial words, like fotke instead of fotografije, and par instead of nekoliko?

Yes, in informal speech you could say:

Na mreži imam par pratitelja koji vole moje fotke.

Colloquial changes:

par – literally a pair, but commonly used for a couple of, a few. Slightly vaguer than nekoliko, which feels a bit more neutral/standard.
fotke – diminutive/colloquial for photographs, pics. Very common in speech and informal writing.

Grammar still applies:

par pratitelja – par, like nekoliko, takes genitive plural (pratitelja).
moje fotke – fotke is still feminine plural, so moje is the right form.

The style just becomes more casual.

Is imam nekoliko pratitelja neutral, positive, or does it sound like only a few?

Nekoliko is fairly neutral: it simply means several / a few, usually more than 2 but not many.

Nuances:

imam nekoliko pratitelja – neutral statement: I have several followers.
imam samo nekoliko pratitelja – adding samo (only) makes it sound modest or negative: I only have a few followers.
imam par pratitelja – more colloquial, can sound a bit modest or offhand: I’ve got a couple of followers.
imam puno pratitelja – positive, a lot of followers.

So by itself, nekoliko doesn’t imply only unless you add a word like samo.