diff --git a/lib/Properties.hs b/lib/Properties.hs
index 877afe17bdb57462e7cf5c646625236c82fe94a9..241a07634938a2f7fc7b6673eccf05141a48abd2 100644
--- a/lib/Properties.hs
+++ b/lib/Properties.hs
@@ -76,9 +76,10 @@ checkTileset tileset = do
 
   -- reject tilesets unsuitable for workadventure
   unless (tilesetTilewidth tileset == 32 && tilesetTileheight tileset == 32)
-    $ complain $ "Tileset " <> tilesetName tileset <> " must have tile size 32 by 32"
-
+    $ complain $ "Tileset " <> tilesetName tileset <> " must have tile size 32×32"
 
+  unless (tilesetImageheight tileset < 4096 && tilesetImagewidth tileset < 4096)
+    $ warn $ "Tileset " <> tilesetName tileset <> " should not be larger than 4096×4096 pixels in total"
 
 
 -- | Checks a single (custom) property of a layer