Visuals have always been a big part of my writing process.
Often, the visuals will come to me before almost anything else; like the full moon over rows of fields in Killing Season, or the ghost town in the desert in Don't Look For Me.
When I'm planning a new book, I like to gather images together that will help me get a handle on the place, characters and story I'm dreaming up.
It's really helpful for starting to visualise the locations and the world in which the book takes place. Also, it's a lot easier than writing, so yay for productive procrastination.
I've always done this, but it used to be with a mixture of old-fashioned clippings and pics saved in Word docs. For the last couple of books, I've created Pinterest boards as part of the brainstorming process. Quite often, I'll get an idea for a new story strand from an arresting image.
Here's my Pinterest board for Presumed Dead. I hope it gives you a flavour of the feel of the book.
(Yes, I have a board in progress for my 2019 book. No, I'm not showing anyone yet.)