Ŝi redaktas la bildon por ŝanĝi la kontraston.

The ending -n marks the direct object in Esperanto.

• la bildon = the image that she is editing
• la kontraston = the contrast that is being changed

So in this sentence, both nouns are receiving the action of a verb. This is one of the most important uses of -n in Esperanto.

-as is the present-tense verb ending.

So redaktas means edits / is editing.

A useful point for English speakers: Esperanto verbs do not change for person.

• mi redaktas = I edit
• ŝi redaktas = she edits
• ili redaktas = they edit

The ending stays -as every time.

Because ŝanĝi is the infinitive form, ending in -i.

After por, Esperanto often uses an infinitive to show purpose:

• por ŝanĝi la kontraston = to change the contrast / in order to change the contrast

If you used ŝanĝas, that would be a normal present-tense verb, and the structure would not fit here.

In Esperanto, the infinitive is built into the verb ending -i itself.

So:

• ŝanĝi = to change
• redakti = to edit
• vidi = to see

English needs a separate word to, but Esperanto does not.

Here por shows purpose.

So por ŝanĝi la kontraston means:

• to change the contrast
• in order to change the contrast

In many sentences, por can often be translated as for, but in this kind of structure it is very often best understood as to or in order to.

La is the Esperanto word for the.

It appears twice because the sentence refers to two specific things:

• la bildon = the image
• la kontraston = the contrast

Esperanto has no word for a or an, but it does use la when something is definite or specific.

Here, la kontraston sounds natural because it means the specific contrast of that image.

Because por ŝanĝi la kontraston is an infinitive phrase, not a full clause.

In Esperanto, when the subject is understood from the main clause, you usually do not repeat it.

So this works naturally:

• Ŝi redaktas la bildon por ŝanĝi la kontraston.

If you wanted a full clause with its own subject, you could use por ke plus a verb in -u:

• Ŝi redaktas la bildon por ke ŝi ŝanĝu la kontraston.

That is grammatical, but the original infinitive version is simpler and more common here.

Yes, Esperanto word order is fairly flexible, partly because -n marks the direct object.

The most neutral order here is:

• Ŝi redaktas la bildon por ŝanĝi la kontraston.

But you could also say:

• Por ŝanĝi la kontraston, ŝi redaktas la bildon.

That puts more emphasis on the purpose. Even though word order can move around, the original version is the most straightforward and natural for a learner.

• ŝ sounds like sh in shoe
• ĝ sounds like j in judge

So:

• ŝi sounds roughly like shee
• ŝanĝi sounds roughly like SHAHN-jee

Also, Esperanto normally stresses the second-to-last syllable:

• reDAKtas
• BILdon
• ŜANĝi
• konTRASton

Yes, it is understandable and acceptable, especially in computer or software contexts.

Redakti often means to edit, and many speakers use it for things like text, images, or other digital content. Depending on context, some speakers might also choose words like modifi or prilabori, but redaktas la bildon is perfectly clear.