1. Open up any two photos, both being same size but is not a must. Choose one photo as your main photo you wish to display.
the second photo will be the faded background Second.
2. Then highlight the photo you wish to use as your faded background image.
and cut that image or copy to clipboard.-
3. Highlight the main photo(image top)and
Paste As new layer. It should completely cover the main photo.
4. Move that pic to one side of window to make room for layer window.
5. Now click on layers , go down to Properties.
Go down to Properties. →
6. On layers properties General Tab, choose Opacity.
Start it by sliding to about 50% ½ or so.