Me, describing a picture ofrom my yellow grammar book Me, describing a picture from my yellow grammar book

Today I would like to describe thisa picture to you from my yellow grammar book. Today I would like to describe a picture to you from my yellow grammar book.

"this picture" would be referring to a specific already known picture. If this was an in-person conversation, where you were holding the picture or pointing to it, that would be sufficient to introduce it, but since this is purely writing and it's the first time you're mentioning it, it sounds a little off to say "this" before you've introduced the picture to the conversation.

The question asks the reader to carefully take a look at the picture and describe what Iit was (or "I see" because I'm actually seeing it now) The question asks the reader to carefully take a look at the picture and describe what it was (or "I see" because I'm actually seeing it now)

"quest" is a heroic mission, like trying to save the world. You can't use it as a shortening of question. asks needs a person that's being asked. "what I was" would be describing yourself, not the picture.

Firstly, on the western side are illustratedtwo girls are depicted: Lily and Ava Alternatively: "The western side depicts two girls: Lily and Ava" Firstly, on the western side two girls are depicted: Lily and Ava Alternatively: "The western side depicts two girls: Lily and Ava"

Depicted is more natural than illustrated, it's basically a more formal version of "shown", and the important thing is their presence, not the type of art used to the produce the picture. By saying "are illustrated depicted" you've changed the verb to be intransitive. This means the "two girls" are the subject (they are "doing" "being depicted"), not the object, and English is SVO, subject, verb, object. Alternatively, you can keep the image as the subject, but then you need to use the transitive "depicts" instead of "are depicted". Once you do that, the girls become the object again.

Ava is also the second tallest person in the picture, beforeahead of Liam, whose height almost reaches a tree(that of a tree / the top of a tree). Ava is also the second tallest person in the picture, ahead of Liam, whose height almost reaches (that of a tree / the top of a tree).

"reaches" here should be used for a specific point or measurement, rather than a thing. By saying "that of a tree" you're basically saying "the height of a tree", but using "that" instead of repeating "the height". (It's ok to say "reaches a tree" if you're talking about Ava moving _towards_ a tree, just not for comparing measurements like height)

On the left centrecenter left of the image, there are Ben and Finn are there. On the center left of the image, Ben and Finn are there.

While both "left" and "centre" can be used as nouns and adjectives, while using them together, it's more natural to use "centre" as the adjective. "There are Ben and Finn" is logically valid by grammar rules, but English prefers active sentences rather than passive sentences, so it's better to use Ben and Finn as a subject.

(We can see?) Ben doesn't have good taste in terms of styling because of his green sweater. (We can see?) Ben doesn't have good taste in terms of styling because of his green sweater.

"because of his green sweater" implies the sweater is the direct cause of his bad taste, but I think your intent here is that the green sweater is the cause of your opinion of his taste, so it's more natural to add more to clarify that.

Zoe is seated at Alex's right and Lucy is in front of him. Zoe is seated at Alex's right and Lucy is in front of him.

Meanwhile, Liucy seems completely lost in her thoughts, handling a knife in front of a smiling Alex. Meanwhile, Lucy seems completely lost in her thoughts, handling a knife in front of a smiling Alex.