Index: /trunk/src/org/openstreetmap/josm/gui/layer/AbstractTileSourceLayer.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/gui/layer/AbstractTileSourceLayer.java	(revision 17491)
+++ /trunk/src/org/openstreetmap/josm/gui/layer/AbstractTileSourceLayer.java	(revision 17492)
@@ -145,4 +145,5 @@
 implements ImageObserver, TileLoaderListener, ZoomChangeListener, FilterChangeListener, DisplaySettingsChangeListener {
     private static final String PREFERENCE_PREFIX = "imagery.generic";
+    private static final int MAX_TILES_SPANNED = 40;
     static { // Registers all setting properties
         new TileSourceDisplaySettings();
@@ -1234,5 +1235,5 @@
 
         private boolean tooLarge() {
-            return insane() || this.tilesSpanned() > 20;
+            return insane() || this.tilesSpanned() > MAX_TILES_SPANNED;
         }
 
@@ -1290,5 +1291,5 @@
             if (tooLarge()) {
                 // Too many tiles... refuse to download
-                Logging.warn("Not downloading all tiles because there is more than 18 tiles on an axis!");
+                Logging.warn("Not downloading all tiles because there is more than {0} tiles on an axis!", MAX_TILES_SPANNED);
                 return;
             }