use a symlink to Saint_of_Killer's titlepic.gif rather than a ppm copy

use gifs instead of ppms, like the rest of the build system (this is a
relic from ppmcaption anyway)

graphics/titlepic/Makefile

@@ -1,12 +1,12 @@
-titlepic: freedoom.ppm freedm.ppm
+titlepic: freedoom.gif freedm.gif
 
-freedoom.ppm: base.ppm
+freedoom.gif: titlepic.gif
 	./create_caption Freedoom $@
 
-freedm.ppm: base.ppm
+freedm.gif: titlepic.gif
 	./create_caption FreeDM $@
 
 clean:
-	rm -f freedm.ppm freedoom.ppm
+	rm -f freedm.gif freedoom.gif
 
 .PHONY: clean

graphics/titlepic/create_caption

@@ -13,5 +13,5 @@ convert -fill white -font Helvetica-Bold                               \
     -gravity southeast                                                 \
       -draw "text 10,25 'Version: $VERSION'"                           \
       -draw "text 10,5 '$DATE'"                                        \
-    base.ppm $2
+    titlepic.gif $2
 

graphics/titlepic/titlepic.gif

@@ -0,0 +1 @@
+../saint_of_killers/titlepic.gif