Allow images in higher resolution to be stored in own folder

- The is an alternative used in other toolkits

interface/wx/bmpbndl.h

@@ -232,7 +232,8 @@ public:
         Create a bundle from bitmaps stored as files.
 
         Looking in @a path for files using @a filename as prefix and potentionally a
-        suffix with scale, e.g. "_2x" or "@2x"
+        suffix with scale, e.g. "_2x" or "@2x". Alternatively, it will look for
+        files with the same filename in a directory "2.0x/" (@since 3.3.2).
 
         @param path     Path of the directory containing the files
         @param filename Bitmap's filename without any scale suffix

src/common/bmpbndl.cpp

@@ -529,6 +529,12 @@ wxBitmapBundle wxBitmapBundle::FromFiles(const wxString& path, const wxString& f
             fn.SetName(wxString::Format("%s_%dx", filename, dpiFactor));
         }
 
+        if ( !fn.FileExists() && dpiFactor != 1 )
+        {
+            // try /2.0x/image.png naming scheme
+            fn.AppendDir( wxString::Format("%d.0x", dpiFactor));
+        }
+
         if ( fn.FileExists() )
         {
             wxBitmap bmp(fn.GetFullPath(), wxBITMAP_TYPE_ANY);