changed wrong key used retrieving from settings the last used image f…

…ilter, to fix #2901

git-svn-id: http://svn.osgeo.org/qgis/trunk@13957 c8812cc2-4d05-0410-92ff-de0c093fc19c

src/app/qgisapp.cpp

@@ -3462,7 +3462,7 @@ void QgisApp::saveMapAsImage()
 
   //find out the last used filter
   QSettings myQSettings;  // where we keep last used filter in persistent state
-  QString myLastUsedFilter = myQSettings.value( "/UI/saveAsImageFilter" ).toString();
+  QString myLastUsedFilter = myQSettings.value( "/UI/lastSaveAsImageFilter" ).toString();
   QString myLastUsedDir = myQSettings.value( "/UI/lastSaveAsImageDir", "." ).toString();
 
   // get a list of supported output image types