--- a/ThemeFiles.wiki	Sun Dec 07 16:21:00 2014 +0000
+++ b/ThemeFiles.wiki	Sun Dec 07 16:22:26 2014 +0000
@@ -69,7 +69,12 @@
 If an object mask is not provided, the object in question can be destroyed but will, unlike the main terrain, not leave the terrain background texture behind.
 
 === Sprays ===
-Sprays are single images of any size, they will be drawn onto the land texture (by `LandTex.png`). They can have any name as long as it is not any of the other names on this page. Sprays have to be configured in `theme.cfg`.
+Sprays are single images of any size, they will be drawn onto the land texture (by `LandTex.png`). You can choose the file name by yourselves, but it must follow the following rules:
+
+ * It must have the suffix “`.png`”
+ * It must not be equal with any other file name mentioned on this page
+
+Sprays have to be configured in `theme.cfg`.
 
 == Background ==
 === `Sky.png` ===