Index: trunk/src/org/openstreetmap/josm/data/imagery/OffsetBookmark.java
===================================================================
--- trunk/src/org/openstreetmap/josm/data/imagery/OffsetBookmark.java	(revision 3961)
+++ trunk/src/org/openstreetmap/josm/data/imagery/OffsetBookmark.java	(revision 3962)
@@ -13,7 +13,8 @@
 import org.openstreetmap.josm.Main;
 import org.openstreetmap.josm.data.coor.LatLon;
+import org.openstreetmap.josm.data.projection.Mercator;
 import org.openstreetmap.josm.data.projection.Projection;
+import org.openstreetmap.josm.data.projection.ProjectionInfo;
 import org.openstreetmap.josm.data.projection.Projections;
-import org.openstreetmap.josm.data.projection.ProjectionInfo;
 import org.openstreetmap.josm.gui.layer.ImageryLayer;
 
@@ -66,4 +67,9 @@
             this.centerX = Double.valueOf(array.get(5));
             this.centerY = Double.valueOf(array.get(6));
+        }
+        // Mercator scale factor migration
+        if (proj instanceof Mercator && this.dx < 1E-3 && this.dy < 1E-3) {
+            this.dx *= 6378137;
+            this.dy *= 6378137;
         }
         if (proj == null) {