diff --git a/lcl/graphics.pp b/lcl/graphics.pp
index 791b94365a..f4d2143f84 100644
--- a/lcl/graphics.pp
+++ b/lcl/graphics.pp
@@ -44,7 +44,6 @@ uses
   LCLStrConsts, LCLType, LCLProc, LMessages, LCLIntf, LResources, LCLResCache,
   GraphType, IcnsTypes, GraphMath, InterfaceBase, WSReferences;
 
-
 type
   PColor = ^TColor;
   TColor = TGraphicsColor;
@@ -673,7 +672,6 @@ type
   TGraphic = class(TPersistent)
   private
     FModified: Boolean;
-    FTransparent: Boolean;
     FOnChange: TNotifyEvent;
     FOnProgress: TProgressEvent;
     FPaletteModified: Boolean;
@@ -686,7 +684,7 @@ type
     function GetHeight: Integer; virtual; abstract;
     function GetMimeType: string; virtual;
     function GetPalette: HPALETTE; virtual;
-    function GetTransparent: Boolean; virtual;
+    function GetTransparent: Boolean; virtual; abstract;
     function GetWidth: Integer; virtual; abstract;
     procedure Progress(Sender: TObject; Stage: TProgressStage;
       PercentDone: Byte;  RedrawNow: Boolean; const R: TRect;
@@ -697,7 +695,7 @@ type
     procedure ReadData(Stream: TStream); virtual; // used by Filer
     procedure SetHeight(Value: Integer); virtual; abstract;
     procedure SetPalette(Value: HPALETTE); virtual;
-    procedure SetTransparent(Value: Boolean); virtual;
+    procedure SetTransparent(Value: Boolean); virtual; abstract;
     procedure SetWidth(Value: Integer); virtual; abstract;
     procedure SetModified(Value: Boolean);
     procedure WriteData(Stream: TStream); virtual; // used by filer
@@ -1117,6 +1115,7 @@ type
     FTransparentMode: TTransparentMode;
     FUpdateCount: Integer;
     FUpdateCanvasOnly: Boolean;
+    FMasked: Boolean;
 
     procedure CanvasChanging(Sender: TObject);
     procedure CreateCanvas;
@@ -1124,7 +1123,7 @@ type
     procedure FreeCanvasContext;
     function  GetCanvas: TCanvas;
     function  GetRawImage: TRawImage;
-    function GetTransparentColor: TColor;
+    function  GetTransparentColor: TColor;
     procedure SetTransparentColor(AValue: TColor);
   protected
     FSharedImage: TSharedRasterImage;
@@ -1135,6 +1134,7 @@ type
     function GetEmpty: Boolean; override;
     function GetHandle: THandle;
     function GetBitmapHandle: HBITMAP; virtual; abstract;
+    function GetMasked: Boolean; virtual;
     function GetMaskHandle: HBITMAP; virtual; abstract;
     function GetMimeType: string; override;
     function GetPixelFormat: TPixelFormat; virtual; abstract;
@@ -1152,7 +1152,9 @@ type
     function  InternalReleaseMaskHandle: HBITMAP; virtual; abstract;
     function  InternalReleasePalette: HPALETTE; virtual; abstract;
     procedure SetBitmapHandle(AValue: HBITMAP);
+    procedure SetMasked(AValue: Boolean); virtual;
     procedure SetMaskHandle(AValue: HBITMAP);
+    procedure SetTransparent(AValue: Boolean); override;
     procedure UnshareImage(CopyContent: boolean); virtual; abstract;
     function  UpdateHandles(ABitmap, AMask: HBITMAP): Boolean; virtual; abstract; // called when handles are created from rawimage (true when handle changed)
     procedure SaveStreamNeeded;
@@ -1167,7 +1169,7 @@ type
     procedure SetPixelFormat(AValue: TPixelFormat); virtual; abstract;
     procedure WriteData(Stream: TStream); override;
     procedure WriteStream(AStream: TMemoryStream); virtual; abstract;
-    function RequestTransparentColor: TColor;
+    function  RequestTransparentColor: TColor;
   public
     constructor Create; override;
     destructor Destroy; override;
@@ -1199,6 +1201,7 @@ type
     property Canvas: TCanvas read GetCanvas;
     function HandleAllocated: boolean;
     property BitmapHandle: HBITMAP read GetBitmapHandle write SetBitmapHandle;
+    property Masked: Boolean read GetMasked write SetMasked;
     property MaskHandle: HBITMAP read GetMaskHandle write SetMaskHandle;
     property PixelFormat: TPixelFormat read GetPixelFormat write SetPixelFormat default pfDevice;
     property RawImage: TRawImage read GetRawImage; // be carefull with this, modify only within a begin/endupdate
@@ -1260,7 +1263,6 @@ type
     function GetPixelFormat: TPixelFormat; override;
     function GetRawImagePtr: PRawImage; override;
     function GetRawImageDescriptionPtr: PRawImageDescription; override;
-    function GetTransparent: Boolean; override;
     procedure HandleNeeded; override;
     function InternalReleaseBitmapHandle: HBITMAP; override;
     function InternalReleaseMaskHandle: HBITMAP; override;
@@ -1464,6 +1466,7 @@ type
     procedure PaletteNeeded; override;
     function GetIndex(AFormat: TPixelFormat; AHeight, AWidth: Word): Integer;
     function GetBitmapHandle: HBITMAP; override;
+    function GetMasked: Boolean; override;
     function GetMaskHandle: HBITMAP; override;
     function GetPalette: HPALETTE; override;
     function GetPixelFormat: TPixelFormat; override;
@@ -1477,6 +1480,7 @@ type
     function InternalReleasePalette: HPALETTE; override;
     procedure ReadData(Stream: TStream); override;
     procedure ReadStream(AStream: TMemoryStream; ASize: Longint); override;
+    procedure SetMasked(AValue: Boolean); override;
     procedure SetPixelFormat(AValue: TPixelFormat); override;
     procedure SetTransparent(Value: Boolean); override;
     procedure UnshareImage(CopyContent: boolean); override;
diff --git a/lcl/include/buttonglyph.inc b/lcl/include/buttonglyph.inc
index 66bbe99e48..f0521e38db 100644
--- a/lcl/include/buttonglyph.inc
+++ b/lcl/include/buttonglyph.inc
@@ -23,6 +23,7 @@ type
   private
     FOwner: TButtonGlyph;
   protected
+    procedure SetMasked(AValue: Boolean); override;
     procedure SetTransparent(AValue: Boolean); override;
   public
     procedure Assign(ASource: TPersistent); override;
@@ -44,6 +45,14 @@ begin
   inherited SetTransparent(True);
 end;
 
+procedure TGlyphBitmap.SetMasked(AValue: Boolean);
+begin
+  if (FOwner = nil)
+  or (FOwner.FTransparentMode = gtmGlyph)
+  then inherited SetMasked(AValue)
+  else inherited SetMasked(FOwner.FTransparentMode = gtmTransparent);
+end;
+
 procedure TGlyphBitmap.SetTransparent(AValue: Boolean);
 begin
   if (FOwner = nil)
diff --git a/lcl/include/custombitmap.inc b/lcl/include/custombitmap.inc
index 47f912f146..8c4f82e743 100644
--- a/lcl/include/custombitmap.inc
+++ b/lcl/include/custombitmap.inc
@@ -107,10 +107,9 @@ end;
 
 procedure TCustomBitmap.MaskHandleNeeded;
 begin
-  if FMaskHandle <> 0 then exit;
-  // not now, breaks alpha images, since they report themselves as transparent
-  // while no mask is needed
-  // CreateMask;
+  if FMaskHandle <> 0 then Exit;
+  if Masked
+  then CreateMask;
 end;
 
 function TCustomBitmap.PaletteAllocated: boolean;
@@ -229,7 +228,7 @@ procedure TCustomBitmap.SetMonochrome(AValue: Boolean);
 begin
   if Monochrome = AValue then exit;
   if not AValue then Exit;
-  
+
   if AValue
   then PixelFormat := pf1bit
   else PixelFormat := pfDevice;
@@ -301,19 +300,6 @@ begin
   FPixelFormat := TSharedCustomBitmap(FSharedImage).GetPixelFormat;
 end;
 
-function TCustomBitmap.GetTransparent: Boolean;
-begin
-  {$IFDEF VerboseLCLTodos}{$note add better check for transparency }{$ENDIF}
-  // MWE: now tharansparency is set when a maskhandle is assigned, the user can
-  // override this by setting it to false, so no mask is used,
-  // however this meganism ignores the possible alpha channel, so for now 32bit
-  // bitmaps are considered transparent
-  // todos:
-  //  check for device transparency
-  //  check for transparency through palette etc.
-  Result := (FPixelFormat = pf32bit) or inherited GetTransparent;
-end;
-
 function TCustomBitmap.GetMonochrome: Boolean;
 begin
   RawImageNeeded(False);
diff --git a/lcl/include/graphic.inc b/lcl/include/graphic.inc
index 57612c1348..3663cf9f0f 100644
--- a/lcl/include/graphic.inc
+++ b/lcl/include/graphic.inc
@@ -261,11 +261,6 @@ begin
   SaveToStream(Stream);
 end;
 
-function TGraphic.GetTransparent: Boolean;
-begin
-  Result := FTransparent;
-end;
-
 function TGraphic.LazarusResourceTypeValid(const AResourceType: string): boolean;
 begin
   Result := False;
@@ -279,12 +274,4 @@ begin
     FModified := False;
 end;
 
-procedure TGraphic.SetTransparent(Value: Boolean);
-begin
-  if Value <> FTransparent then begin
-    FTransparent := Value;
-    Changed(Self);
-  end;
-end;
-
 // included by graphics.pp
diff --git a/lcl/include/icon.inc b/lcl/include/icon.inc
index a4faae9fe5..39098bbebb 100644
--- a/lcl/include/icon.inc
+++ b/lcl/include/icon.inc
@@ -429,6 +429,12 @@ begin
   Result := TSharedIcon(FSharedImage).GetIndex(AFormat, AHeight, AWidth);
 end;
 
+function TCustomIcon.GetMasked: Boolean;
+begin
+  // per definition an icon is maked, but maybe we should make it settable for alpha images
+  Result := True;
+end;
+
 function TCustomIcon.GetMaskHandle: HBITMAP;
 begin
   if FCurrent = -1
@@ -738,6 +744,11 @@ begin
   {$IFDEF VerboseLCLTodos}{$note Implement me (or raise exception)}{$ENDIF}
 end;
 
+procedure TCustomIcon.SetMasked(AValue: Boolean);
+begin
+  // nothing
+end;
+
 function TCustomIcon.GetBestApplicationIndex: Integer;
 var
   BestCX, BestCY, BestDepth, i, dx, dy, dd: Integer;
diff --git a/lcl/include/rasterimage.inc b/lcl/include/rasterimage.inc
index c12e8c4204..489ef9fd0c 100644
--- a/lcl/include/rasterimage.inc
+++ b/lcl/include/rasterimage.inc
@@ -60,9 +60,9 @@ begin
       else UpdateHandles(0, 0);
     end;
 
-    FTransparent := SrcImage.FTransparent;
     FTransparentMode := SrcImage.FTransparentMode;
     FTransparentColor := SrcImage.FTransparentColor;
+    FMasked := SrcImage.FMasked;
 
     // -> check if already shared
     if SrcImage.FSharedImage <> FSharedImage
@@ -258,7 +258,7 @@ begin
   BitmapHandleNeeded;
   if not BitmapHandleAllocated then Exit;
 
-  if Transparent then
+  if Masked then
     UseMaskHandle:=MaskHandle
   else
     UseMaskHandle:=0;
@@ -501,16 +501,21 @@ begin
 end;
 
 function TRasterImage.GetTransparent: Boolean;
+var
+  Desc: PRawImageDescription;
 begin
-  {$IFDEF VerboseLCLTodos}{$note add better check for transparency}{$ENDIF}
-  // MWE: now tharansparency is set when a maskhandle is assigned, the user can
-  // override this by setting it to false, so no mask is used,
-  // however this meganism ignores the possible alpha channel, so for now 32bit
-  // bitmaps are considered transparent
-  // todos:
-  //  check for device transparency
-  //  check for transparency through palette etc.
-  Result := FTransparent;
+  if Masked
+  then begin
+    // postpone description generation since we know we are transparent here
+    Result := True
+  end
+  else begin
+    Desc := GetRawImageDescriptionPtr;
+    Result := (Desc <> nil)
+          and (Desc^.Format <> ricfNone)
+          and (Desc^.AlphaPrec > 0);
+    //TODO:  check for transparency through palette etc.
+  end;
 end;
 
 function TRasterImage.GetWidth: Integer;
@@ -625,6 +630,32 @@ begin
   else SetHandles(0, AValue);
 end;
 
+procedure TRasterImage.SetMasked(AValue: Boolean);
+begin
+  if AValue = Masked then Exit;
+
+  FMasked := AValue;
+  Changed(Self);
+end;
+
+procedure TRasterImage.SetTransparentMode(AValue: TTransparentMode);
+begin
+  if AValue = TransparentMode then exit;
+  FTransparentMode := AValue;
+
+  if AValue = tmAuto
+  then TransparentColor := clDefault
+  else TransparentColor := RequestTransparentColor;
+end;
+
+procedure TRasterImage.SetTransparent(AValue: Boolean);
+begin
+  if AValue = Transparent then Exit;
+
+  // some delphi compatibility, we can only change transparency through the mask.
+  Masked := AValue;
+end;
+
 // release handles without freeing them
 // useful for creating a HBitmap
 function TRasterImage.ReleaseBitmapHandle: HBITMAP;
@@ -756,6 +787,11 @@ begin
   else Result := Desc^.Height;
 end;
 
+function TRasterImage.GetMasked: Boolean;
+begin
+  Result := FMasked;
+end;
+
 class function TRasterImage.GetSharedImageClass: TSharedRasterImageClass;
 begin
   Result := TSharedRasterImage;
@@ -879,15 +915,5 @@ begin
   SetSize(Width, AHeight);
 end;
 
-procedure TRasterImage.SetTransparentMode(AValue: TTransparentMode);
-begin
-  if AValue = TransparentMode then exit;
-  FTransparentMode := AValue;
-
-  if AValue = tmAuto
-  then TransparentColor := clDefault
-  else TransparentColor := RequestTransparentColor;
-end;
-
 // included by graphics.pp
 
diff --git a/lcl/interfaces/gtk/gtkproc.inc b/lcl/interfaces/gtk/gtkproc.inc
index 3a0e2f91ae..afced7e572 100644
--- a/lcl/interfaces/gtk/gtkproc.inc
+++ b/lcl/interfaces/gtk/gtkproc.inc
@@ -5805,6 +5805,7 @@ var
   AImageList: TCustomImageList;
   FreeImageList: Boolean;
   AImageIndex: Integer;
+  ItemBmp: TBitmap;
 begin
   if (MenuItem=nil) then
     exit;
@@ -5845,9 +5846,13 @@ begin
   if AImageList = nil then
   begin
     AImageList := TImageList.Create(nil);
-    AImageList.Width := LCLMenuItem.Bitmap.Width; // maybe height to prevent too wide bitmaps?
-    AImageList.Height := LCLMenuItem.Bitmap.Height;
-    AImageIndex := AImageList.Add(LCLMenuItem.Bitmap, nil);
+    // prevent multiple calls to GetBitmap;
+    ItemBmp := LCLMenuItem.Bitmap;
+    AImageList.Width := ItemBmp.Width; // maybe height to prevent too wide bitmaps?
+    AImageList.Height := ItemBmp.Height;
+    if ItemBmp.Masked
+    then AImageIndex := AImageList.AddMasked(ItemBmp, ItemBmp.TransparentColor)
+    else AImageIndex := AImageList.Add(ItemBmp, nil);
     FreeImageList := True;
   end
   else