Unsplash photos published before June 8, 2017 are CC0 (public domain):

Ashim D'Silva <https://unsplash.com/photos/WeYamle9fDM>
Canazei Granite Ridges <https://unsplash.com/photos/yrwpJwDNSHE>
Mr. Lee <https://unsplash.com/photos/v7r8kZStqFw>
Photo by SpaceX <https://unsplash.com/photos/VBNb52J8Trk>
Sunset by the Pier <https://unsplash.com/photos/ces8_Bo7bhQ>

Unsplash photos published on or after June 8, 2017 are free to use, modify, and redistribute subject to the Unsplash license <https://unsplash.com/license>:

Martin Adams <https://unsplash.com/photos/MpTdvXlAsVE>
Morskie Oko <https://unsplash.com/photos/_1UF_3TlKcQ>
Nattu Adnan <https://unsplash.com/photos/Ai2TRdvI6gM>
Tj Holowaychuk <https://unsplash.com/photos/iGrsa9rL11o>
Viktor Forgacs <https://unsplash.com/photos/q8XSCZYh6D8>
“A Large Body of Water Surrounded By Mountains” by Peter Thomas <https://unsplash.com/photos/Dxod5pdRtsk>
“A Trail of Footprints In The Sand” by David Emrich <https://unsplash.com/photos/A9mr3TPoj0k>
“Photo of Valley” by Aniket Doele <https://unsplash.com/photos/M6XC789HLe8>

Pexels photos are free to use, modify, and redistribute subject to the Pexels license <https://www.pexels.com/license/>:

Snow-Capped Mountain <https://www.pexels.com/photo/photo-of-snow-capped-mountain-during-evening-2440024/>