Learn Dutch: Wij zullen de voorgrond van de foto veranderen. - We will change the foreground of the photo.

How would we spell the past participle of veranderen if we used it as an adjective to say 'the changed foreground', relating to this lesson's rules?

The past participle is veranderd. When placed before the de-word voorgrond, it gets an -e ending, becoming de veranderde voorgrond. Because the syllable before the -d contains an unaccented schwa sound, we don't need to apply any vowel or consonant shifts. This is unlike a word like vergroot, which drops a vowel in the open syllable to become vergrote.

We use zullen here for 'will change'. Could we just use the present tense?

Yes, but usually only if you add a time indicator. Dutch frequently uses the simple present for the future (e.g., Wij veranderen de voorgrond morgen). Without a time word in the sentence, using zullen is the most natural way to clarify that this is a future intention or promise.

If we wanted to say 'We have changed the foreground', does veranderen use hebben or zijn as its auxiliary verb?

It uses hebben here because there is a direct object receiving the action (de voorgrond): Wij hebben de voorgrond veranderd. However, when veranderen indicates a change of state without a direct object (e.g., 'The foreground has changed'), it takes zijn: De voorgrond is veranderd.

Why use instead of gluing the words together into a compound noun like ?