But if the actual writing of the book [A Little Life] was brief, it’s only now that I realize that I had been thinking of this novel for far longer. I began collecting photography when I was 26, 14 years ago; and when I actually began writing, it was these images I returned to, again and again: They provided a sort of tonal sound check, as it were — was I conveying in words and scenes what I felt when I saw these photographs and paintings? Now that the book is done, I realize that these images are now so inextricable from the book — and my experience of writing it — that looking at them again is somehow jolting: They’ve become a visual diary of that year and a half, and I find myself unable to look at them without thinking of the life of my novel.
Hanya Hanagihara: How I Wrote My Novel: Hanya Yanagihara’s A Little Life, Vulture April 28/2015
(from here) .. where you can see the images that influenced the writing of the novel