updated README and Screenshots (#1111)

3d/README.md

@@ -3,5 +3,3 @@
 These demos are all 3D, but otherwise do not have a common theme.
 
 Languages: All are GDScript
-
-Renderers: All use Forward+

3d/navigation/README.md

@@ -7,10 +7,10 @@ Code is provided for polyline following in 3D.
 
 Language: GDScript
 
-Renderer: Forward+
+Renderer: Compatibility
 
 Check out this demo on the asset library: https://godotengine.org/asset-library/asset/2743
 
 ## Screenshots
 
-![Screenshot](screenshots/nav.png)
+![Screenshot](screenshots/navigation.webp)

viewport/3d_in_2d/README.md

@@ -19,4 +19,4 @@ which is then assigned to the sprite's texture.
 
 ## Screenshots
 
-![Screenshot](screenshots/3d_in_2d.png)
+![Screenshot](screenshots/3d_in_2d.webp)