Question about «The portrait utilizes a palette of...»

Your sentence is correct. It is a figure of speech called personification which is commonly used. Look at this example:

The picture utilizes a pyramidal arrangement common of High Renaissance artists, although Leonardo's perfection of anatomical movement and fluidity elevates the figures with a sense of realistic motion.

However, the expression itself is rarely used, as Gngram finds no instances of it in written texts.

Note: It can be utilizes (AmE) or utilises (BrE).