"Ozymandias" was inspired by a statue, and it's no surprise that art is one of this poem's themes. The traveler makes a point of telling us that the statue was made by a really skilled sculptor, and the poem as a whole explores the question of art's longevity. The statue is in part a stand-in or substitute for all kinds of art (painting, poetry, etc.), and the poem asks us to think not just about sculpture, but about the fate of other arts as well.
The sculptor is similar to the reader of the poem because both engage in the processes of reading and interpretation.