NASA has a massive library of amazing photos and they are right there for us to use! Read the fine print because there are some restrictions but for the most part we can use them for non-commercial purposes. I have always loved this sort of picture…
And the earth from space is also pretty darned interesting!
I was reminded about these free NASA images by John McWade. You should watch his free video about how he made calendars using these images. I read all of his issues of Before & After, published over the last many years. I learned so much about graphic design, text, and layout from him! He is now at Lynda.com and I wish him years of happiness there.