Το διαμέρισμα είναι πιο ήσυχο απ' όσο φαίνεται στη φωτογραφία.

Because διαμέρισμα is a neuter noun, and the adjective has to match it in gender, number, and case.

• το διαμέρισμα = the apartment → neuter singular
• so: ήσυχο = quiet, neuter singular

Compare:

• ο δρόμος είναι ήσυχος = the street is quiet
• η γειτονιά είναι ήσυχη = the neighborhood is quiet
• το διαμέρισμα είναι ήσυχο = the apartment is quiet

In this sentence, πιο ήσυχο means quieter.

πιο + adjective is the normal way to form the comparative in Modern Greek.

So:

• ήσυχο = quiet
• πιο ήσυχο = quieter / more quiet

This is very common:

• μεγάλο → πιο μεγάλο = bigger
• όμορφο → πιο όμορφο = more beautiful
• ήσυχο → πιο ήσυχο = quieter

Greek sometimes also has a one-word comparative form, but πιο + adjective is the standard, everyday pattern.

Here απ' όσο introduces a comparison with a whole clause, not just with a noun.

• πιο ήσυχο από το άλλο διαμέρισμα = quieter than the other apartment
  → comparison with a noun phrase

• πιο ήσυχο απ' όσο φαίνεται = quieter than it appears
  → comparison with a clause

So όσο is needed because the second part is not just than X, but more like than/as much as it seems.

Also, απ' is just the shortened form of από before a vowel:

• από όσο
• απ' όσο

Both are understood, but the shortened form is very common.

In this sentence, όσο is part of a comparative structure and means something like than in English, but more literally it has the sense of as much as.

So:

• πιο ήσυχο απ' όσο φαίνεται
  literally: quieter than/as much as it seems
• natural English: quieter than it looks/seems

This use of όσο is common after comparatives:

• Είναι πιο δύσκολο απ' όσο νόμιζα. = It’s more difficult than I thought.
• Ήταν καλύτερο απ' όσο περίμενα. = It was better than I expected.

Yes, φαίνεται looks like a passive/middle form, and in Modern Greek it often functions that way. The verb φαίνομαι means to appear, to seem, or sometimes to look.

So:

• φαίνεται = it appears / it seems / it looks

In this sentence:

• Το διαμέρισμα ... φαίνεται στη φωτογραφία means something like
• the apartment appears / looks in the photo

Greek often uses φαίνομαι where English uses look or seem:

• Φαίνεται κουρασμένος. = He looks tired.
• Μου φαίνεται καλό. = It seems good to me.

Because στη is the contracted form of σε τη.

So:

• σε + τη = στη
• σε + το = στο
• σε + τον = στον

Therefore:

• στη φωτογραφία = in the photo / on the photo, depending on context

This contraction is standard in Modern Greek and used all the time.

In natural English, it is usually translated as in the photo.

Greek σε can cover meanings that English expresses with different prepositions depending on context. So στη φωτογραφία here means:

• in the photo
• as seen in the photo

So the whole phrase φαίνεται στη φωτογραφία is basically it looks in the photo or it appears in the photo.

Yes, in principle Greek can form some comparatives with endings like -ότερος, so you may sometimes see forms like ησυχότερο.

However, πιο ήσυχο is the most common and natural everyday way to say quieter.

So for learners, the safest pattern is:

• πιο + adjective

Examples:

• πιο μικρό = smaller
• πιο γρήγορο = faster
• πιο ήσυχο = quieter

You should definitely recognize the one-word comparatives when you see them, but producing πιο + adjective is usually easiest and most idiomatic.

The sentence breaks down like this:

• Το διαμέρισμα = the apartment
• είναι = is
• πιο ήσυχο = quieter
• απ' όσο φαίνεται = than it appears / than it looks
• στη φωτογραφία = in the photo

So the structure is:

subject + verb + comparative adjective + comparative clause + extra phrase

More literally:

• The apartment is quieter than it appears in the photo.

Natural English:

• The apartment is quieter than it looks in the photo.

Because Greek often leaves out subject pronouns when they are understood from the verb form or the context.

In English, you must say:

• it looks
• it seems

In Greek, the verb form itself can already imply the subject:

• φαίνεται = it appears / it seems

Since the sentence is already about το διαμέρισμα, there is no need to repeat a separate word for it.

This is very normal in Greek:

• Είναι μεγάλο. = It is big.
• Φαίνεται ωραίο. = It looks nice.

Yes, Greek word order is more flexible than English, although this version is the most neutral and natural.

For example, στη φωτογραφία could sometimes be moved for emphasis:

• Το διαμέρισμα είναι πιο ήσυχο απ' όσο φαίνεται στη φωτογραφία.
• Το διαμέρισμα είναι πιο ήσυχο στη φωτογραφία απ' όσο φαίνεται. ← this would sound odd or change the emphasis, so not every change is equally good

So while Greek word order is flexible, it is not random. The original sentence is the clearest and most natural way to express the idea.

It can do both.

ήσυχος / ήσυχη / ήσυχο can mean:

• quiet, in the sense of not noisy
• calm, peaceful, tranquil

With διαμέρισμα, it usually means not noisy or peaceful to live in.

So here it suggests that the apartment is calmer or less noisy than the photo might make you think.