Imagination is mediated by, arises out of, and/or is informed by the psyche. It is difficult to separate imagination, creativity, and the psyche. C. G. Jung stated that psyche is image.
In her book, The Artist’s Way, Julia Cameron reminds the creative person (who is all of us) to nurture the imagination; tend it; give it space to play; take it on a date. When you have need to dip into the well of your imagination, ensure that it has not become dust.
I am currently reading Philosophies of India by Heinrich Zimmer. The Indian mythologies are teeming with images: literary, visual, poetic. It occurs to me as I am reading it that the expanse of the images of Indian mythology is as broad as the subcontinent of India itself which supports these rich mythologies.
By delving into mythology you may hit the mother lode of images.
I do not want to “should” on you (see Friedrich Nietzsche, Thus Spake Zarathustra, “The Three Metamorphoses”, i.e. kill the dragon “thou shalt.”). What I do is offer is a pearl of wisdom. You choose to accept, reject, or revisit it at a later date.
Replenish your well.
And, mythology is not a bad place to start.