To see a preview: http://www.parks.wa.gov/190/2015-State-Parks-Calendar. Calendars are $18.99 each.
To purchase online, visit http://myprint.wa.gov/. You’ll need to create an account. Once you are logged in, search for “2015 WA State Parks Wall Calendar”.
If that is too complicated, just call State Parks Headquarters at (360) 902-8500.
(BTW: The photos were donated and photographers don't receive any proceeds from the sale of the calendars)