1. Click to Open image.
2. Right-click on image.
3. Scroll to "Set as Wallpaper".l
1. Click on photo.
2. Control click > "Save Image As..."
3. Select your home folder, select
Library sub-folder and then select "Desktop Folder" sub-folder and
save the image there.
4. In the System Preferences in the Dock, select the picture from
the Desktop and Screensaver pane.