diff --git a/src/common/artprov.cpp b/src/common/artprov.cpp
index 7ff0a2785e..c8fd5fe80b 100644
--- a/src/common/artprov.cpp
+++ b/src/common/artprov.cpp
@@ -223,7 +223,10 @@ void wxArtProvider::RescaleBitmap(wxBitmap& bmp, const wxSize& sizeNeeded)
 #else // !wxUSE_IMAGE
     // Fallback method of scaling the bitmap
     wxBitmap newBmp(sizeNeeded);
+#if defined(__WXMSW__) || defined(__WXOSX__)
+    // wxBitmap::UseAlpha() is used only on wxMSW and wxOSX.
     newBmp.UseAlpha(bmp.HasAlpha());
+#endif // __WXMSW__ || __WXOSX__
     {
         wxMemoryDC dc(newBmp);
         double scX = (double)sizeNeeded.GetWidth() / bmp.GetWidth();
diff --git a/src/propgrid/property.cpp b/src/propgrid/property.cpp
index 3b8a6bbcc0..f8973cd1f6 100644
--- a/src/propgrid/property.cpp
+++ b/src/propgrid/property.cpp
@@ -2209,7 +2209,7 @@ void wxPGProperty::SetValueImage( wxBitmap& bmp )
 
         if ( imSz.y != maxSz.y )
         {
-        #if wxUSE_IMAGE
+#if wxUSE_IMAGE
             // Here we use high-quality wxImage scaling functions available
             wxImage img = bmp.ConvertToImage();
             double scaleY = (double)maxSz.y / (double)imSz.y;
@@ -2217,17 +2217,20 @@ void wxPGProperty::SetValueImage( wxBitmap& bmp )
                         wxRound(bmp.GetHeight()*scaleY),
                         wxIMAGE_QUALITY_HIGH);
             wxBitmap* bmpNew = new wxBitmap(img);
-        #else
+#else // !wxUSE_IMAGE
             // This is the old, deprecated method of scaling the image
             wxBitmap* bmpNew = new wxBitmap(maxSz.x,maxSz.y,bmp.GetDepth());
+#if defined(__WXMSW__) || defined(__WXOSX__)
+            // wxBitmap::UseAlpha() is used only on wxMSW and wxOSX.
             bmpNew->UseAlpha(bmp.HasAlpha());
+#endif // __WXMSW__ || __WXOSX__
             {
                 wxMemoryDC dc(*bmpNew);
                 double scaleY = (double)maxSz.y / (double)imSz.y;
                 dc.SetUserScale(scaleY, scaleY);
                 dc.DrawBitmap(bmp, 0, 0);
             }
-        #endif
+#endif // wxUSE_IMAGE/!wxUSE_IMAGE
 
             m_valueBitmap = bmpNew;
         }