Pikseloj gravas por la rezolucio.

Because -o is the normal noun ending in Esperanto, and -j marks the plural.

So:

• pikselo = pixel
• pikseloj = pixels

This is one of the most regular parts of Esperanto grammar: nouns always end in -o, and plurals add -j.

In Esperanto, verbs do not change according to number or person.

So:

• mi gravas = I matter / I am important
• ĝi gravas = it matters / it is important
• pikseloj gravas = pixels matter / pixels are important

The ending -as simply shows the present tense. It does not change for singular or plural subjects.

Gravas comes from gravi, which means to matter or to be important.

So Pikseloj gravas can be understood as:

• Pixels matter
• Pixels are important

English often uses either expression, and Esperanto uses gravi very naturally for this idea.

Both are possible, but they are slightly different in structure:

• Pikseloj gravas = Pixels matter / Pixels are important
• Pikseloj estas gravaj = Pixels are important

The first uses the verb gravi directly.
The second uses esti (to be) plus the adjective gravaj (important, plural).

Both are grammatical. Gravas is a very natural, compact way to say that something matters.

Por usually means for.

So:

• por la rezolucio = for the resolution

In this sentence, it means that pixels matter with regard to resolution, or for determining resolution.

Depending on context, a natural English translation could be:

• Pixels matter for the resolution
• Pixels are important for the resolution
• Pixels matter when it comes to resolution

Because la rezolucio is the object of the preposition por.

After a preposition like por, Esperanto normally uses the basic noun form, not the accusative -n.

So:

• por la rezolucio = correct
• por la rezolucion = not correct in this sentence

The -n ending is mainly used for a direct object or for certain motion expressions, but not here.

La is the definite article, meaning the.

So la rezolucio means the resolution.

It suggests a specific resolution, or resolution understood from context, such as the resolution of a screen, image, or display being discussed.

In some contexts, Esperanto can also omit la if speaking more generally, but with the sentence as given, la rezolucio sounds like a particular, understood resolution.

Yes. Esperanto often takes international or widely known roots and adapts them to Esperanto spelling and word endings.

So pixel becomes pikselo:

• p stays p
• x is written as ks
• the noun ending -o is added

That is completely normal Esperanto word formation.

A simple pronunciation guide is:

pik-SE-loy

More exactly:

• pi like pee
• ks like the x sound in box
• e like e in met
• loj roughly like loy

And remember that Esperanto stress normally falls on the second-to-last syllable, so:

pik-SE-loj

Yes, Esperanto word order is fairly flexible because endings show grammatical roles clearly.

The normal order here is:

• Pikseloj gravas por la rezolucio.

But other orders are possible for emphasis, such as:

• Por la rezolucio gravas pikseloj.

Still, the original order is the most straightforward and natural for a learner.

Here gravas most likely means matter in the sense of being important or relevant, not physically heavy or serious.

So the idea is that pixels are significant when talking about resolution.

That is a very common use of gravi in Esperanto: not just important in a grand sense, but also relevant, significant, or something that makes a difference.