diff --git a/lcl/include/imglist.inc b/lcl/include/imglist.inc
index 44c83ccfd4..b0b9baa769 100644
--- a/lcl/include/imglist.inc
+++ b/lcl/include/imglist.inc
@@ -991,7 +991,8 @@ var
 begin
   SrcHasAlpha := AImage.Description.AlphaPrec > 0;
   KeepAlpha := SrcHasAlpha;
-  if not SrcHasAlpha and (Desc.BitsPerPixel = 32) and (Desc.Depth = 24)
+  if not SrcHasAlpha and (Desc.BitsPerPixel = 32) and (Desc.Depth = 24) and
+    (AImage.Mask <> nil) and (Desc.MaskBitsPerPixel > 0)
   then begin
     // Try to squeeze Aplha channel in some unused bits
     if  (Desc.RedShift >= 8)