Ensure we're using up-to-date tome pof day images in the manual.

(The Dawn one has actually changed visibly, the moon was the wrong way
around.)

doc/manual/manual.txt

@@ -530,13 +530,13 @@ the damage dealt by lawful and chaotic units:
 `-------`----------------------------------------`---------------------`-------`------
 Turn    Image                                    Day-phase             Lawful  Chaotic
 --------------------------------------------------------------------------------------
-1       image:images/schedule-dawn.jpg[]         Dawn                  --      --     
-2       image:images/schedule-morning.jpg[]      Day (morning)         +25%    -25%   
-3       image:images/schedule-afternoon.jpg[]    Day (afternoon)       +25%    -25%    
-4       image:images/schedule-dusk.jpg[]         Dusk                  --      --     
-5       image:images/schedule-firstwatch.jpg[]   Night (first watch)   -25%    +25%   
-6       image:images/schedule-secondwatch.jpg[]  Night (second watch)  -25%    +25%
-Special image:images/schedule-underground.jpg[]  Underground           -25%    +25%
+1       image:images/schedule-dawn.png[]         Dawn                  --      --     
+2       image:images/schedule-morning.png[]      Day (morning)         +25%    -25%   
+3       image:images/schedule-afternoon.png[]    Day (afternoon)       +25%    -25%    
+4       image:images/schedule-dusk.png[]         Dusk                  --      --     
+5       image:images/schedule-firstwatch.png[]   Night (first watch)   -25%    +25%   
+6       image:images/schedule-secondwatch.png[]  Night (second watch)  -25%    +25%
+Special image:images/schedule-underground.png[]  Underground           -25%    +25%
 --------------------------------------------------------------------------------------
 
 Keep in mind that some scenarios take place underground, where it is