The Picture of Dorian Gray embodies the aesthetic ideal as it was praised and preached by the 19th century Pre-Raphaelites, of which Wilde was a follower.
The adjective "aesthetic", however, cannot be used loosely. Something "aesthetic" is defined as something that satisfies the senses. Many erroneously confuse aesthetics with hedonism- the search for pleasure; Wilde tries to explain the difference, but is never understood.
Wilde's views of aesthetics were strongly influenced by Immanuel Kant's Critique of the Power of Judgement (1790) and Analytic of the Beautiful (which is part of the Critique of Judgement). In Kant's theory, beauty must be separated from what is "good", and from what is "agreeable". In other words, beauty is to be isolated and not be used to teach, to analyze, or to critique; just to be admired.
Wilde summarized this by quoting his mentor, Walter Pater in saying "L'Art pour L'Art" (art for art's sake) and by writing the controversial phrase at the end of the prologue of The Picture of Dorian Gray,
Art is quite useless...
With these words, Wild essentially "warns" the readers that Dorian Gray's journey is not a story about morality or immorality. Dorian's is merely the story about a man that engages in the practices of hedonism for the sake of experiencing the true aesthetic goal; finding the beauty of everything. Lord Henry suggests in his own description of what is beauty;
Beauty if a form of Genius [...] People say sometimes that Beauty is only superficial. That may be so. But at least it is not so superficial as Thought is.[..]Beauty is the wonder of wonders. It is only shallow people who do not judge by appearances. The true mystery of the world is the visible, not the invisible.
Let beauty be enjoyed for what it is: a superficial representation of thought, form, and emotion. The problem that Wilde had with Dorian Gray is that, homosexual connotations aside, the presentation of beauty through Dorian's multiple collections of bound books, precious jewels, and exotic paraphernalia fell on deaf ears; the sanctimonious Victorians were not ready to differentiate the moral from the beautiful and thus Wilde received the public scorn.
Aside from Dorian's hunger for beautiful things in his collection of objects, he also hungers for aesthetic experiences. When he meets Sybil, he does not see the woman but the Shakespearean character that she plays.
To-night she is Imogen [...] and tomorrow night she will be Juliet” “When is she Sibyl Vane?” Lord Henry asks......“Never"[responds Dorian]
Notice how, when Sybil Vane kills herself for Dorian, Lord Henry idealizes her death as a form of art. After this incident, Dorian begins to live merely for art's sake.
Someone has killed herself for love of you. I wish that I had ever had such an experience. It would make me in love with love for the rest of my life.
Dorian's admiration for his own personal beauty leads him to trade his soul for beauty, allowing for his beautiful picture to suffer the consequences of his hedonistic acts. Thus, it is his picture and not Dorian what will show his near-demonic search for sensations.
Moreover, he visits opium dens, engages in orgies, drinks, dances, and mainly lives like a sybarite. The search for all the dimensions of beauty are mainly what embody Dorian's personal story; a search for the beauty of emotion, the beauty of things, the beauty of sensations, and the beauty of art imitating life.