diff --git a/lcl/include/bitmap.inc b/lcl/include/bitmap.inc
index 5b4b839f74..77c1df4bfc 100644
--- a/lcl/include/bitmap.inc
+++ b/lcl/include/bitmap.inc
@@ -519,7 +519,7 @@ procedure TBitmap.ReadStream(Stream: TStream; UseSize: boolean; Size: Longint);
   end;
 
 var
-  CacheStream: TStream;
+  WorkStream: TStream;
   StreamType: TBitmapNativeType;
   ReaderClass: TFPCustomImageReaderClass;
   MemStream: TCustomMemoryStream;
@@ -527,24 +527,24 @@ var
   OldPosition: Int64;
 begin
   //debugln('TBitmap.ReadStream Stream=',DbgSName(Stream),' Stream.Size=',dbgs(Stream.Size),' Stream.Position=',dbgs(Stream.Position),' UseSize=',dbgs(UseSize),' Size=',dbgs(Size));
-  CacheStream:=nil;
+  WorkStream:=nil;
   try
     // create mem stream if not already done (to read the image type)
     if (Stream is TCustomMemoryStream) then begin
-      CacheStream:=Stream;
+      WorkStream:=Stream;
     end else if UseSize then begin
-      CacheStream:=TMemoryStream.Create;
-      TMemoryStream(CacheStream).SetSize(Size);
-      CacheStream.CopyFrom(Stream,Size);
-      CacheStream.Position:=0;
+      WorkStream:=TMemoryStream.Create;
+      TMemoryStream(WorkStream).SetSize(Size);
+      WorkStream.CopyFrom(Stream,Size);
+      WorkStream.Position:=0;
     end else begin
       // size is unknown and type is not TMemoryStream
       // ToDo: create cache stream from Stream
-      CacheStream:=Stream;
+      WorkStream:=Stream;
     end;
     // get image type
-    if CacheStream is TCustomMemoryStream then begin
-      MemStream:=TCustomMemoryStream(CacheStream);
+    if WorkStream is TCustomMemoryStream then begin
+      MemStream:=TCustomMemoryStream(WorkStream);
       OldPosition:=MemStream.Position;
       GetSize:=MemStream.Size;
       // workaround for TMemoryStream bug, reading Size sets Position to 0
@@ -563,10 +563,10 @@ begin
     else
       RaiseInvalidBitmapHeader;
     end;
-    ReadStreamWithFPImage(CacheStream,UseSize,Size,ReaderClass);
+    ReadStreamWithFPImage(WorkStream,UseSize,Size,ReaderClass);
   finally
-    if CacheStream<>Stream then
-      CacheStream.Free;
+    if WorkStream<>Stream then
+      WorkStream.Free;
   end;
 end;
 
@@ -704,13 +704,14 @@ begin
   finally
     // set save stream
     FImage.SaveStream:=NewSaveStream;
-    if ReaderClass=TFPReaderBMP then begin
+    if (ReaderClass=TFPReaderBMP) or (ReaderClass=TLazReaderBMP) then begin
       FImage.SaveStreamType:=bnWinBitmap;
       FImage.SaveStreamClass:=TFPWriterBMP;
     end else if ReaderClass=TLazReaderXPM then begin
       FImage.SaveStreamType:=bnXPixmap;
       FImage.SaveStreamClass:=TLazWriterXPM;
     end;
+    //DebugLn('TBitmap.ReadStreamWithFPImage ',DbgSName(FImage.SaveStreamClass),' ',DbgSName(ReaderClass));
     // clean up
     IntfImg.Free;
     ImgReader.Free;
diff --git a/lcl/lresources.pp b/lcl/lresources.pp
index e63862a7a3..f9a38ac614 100644
--- a/lcl/lresources.pp
+++ b/lcl/lresources.pp
@@ -272,9 +272,10 @@ function ConvertLRSExtendedToDouble(p: Pointer): Double;
 procedure ConvertEndianBigDoubleToLRSExtended(BigEndianDouble,
                                               LRSExtended: Pointer);
 
-function ReadLRSByte(s: TStream): byte;
-function ReadLRSWord(s: TStream): word;
 function ReadLRSShortInt(s: TStream): shortint;
+function ReadLRSByte(s: TStream): byte;
+function ReadLRSSmallInt(s: TStream): smallint;
+function ReadLRSWord(s: TStream): word;
 function ReadLRSInteger(s: TStream): integer;
 function ReadLRSCardinal(s: TStream): cardinal;
 function ReadLRSInt64(s: TStream): int64;
@@ -287,7 +288,7 @@ function ReadLRSEndianLittleExtendedAsDouble(s: TStream): Double;
 function ReadLRSValueType(s: TStream): TValueType;
 function ReadLRSInt64MB(s: TStream): int64;// multibyte
 
-procedure WriteLRSShortInt(s: TStream; const i: shortint);
+procedure WriteLRSSmallInt(s: TStream; const i: smallint);
 procedure WriteLRSWord(s: TStream; const w: word);
 procedure WriteLRSInteger(s: TStream; const i: integer);
 procedure WriteLRSCardinal(s: TStream; const c: cardinal);
@@ -2455,6 +2456,12 @@ begin
   end;
 end;
 
+function ReadLRSShortInt(s: TStream): shortint;
+begin
+  Result:=0;
+  s.Read(Result,1);
+end;
+
 function ReadLRSByte(s: TStream): byte;
 begin
   Result:=0;
@@ -2470,11 +2477,11 @@ begin
   {$ENDIF}
 end;
 
-function ReadLRSShortInt(s: TStream): shortint;
+function ReadLRSSmallInt(s: TStream): smallint;
 begin
   Result:=0;
   {$IFDEF FPC_BIG_ENDIAN}
-  Result:=shortint(ReadLRSWord(s));
+  Result:=smallint(ReadLRSWord(s));
   {$ELSE}
   s.Read(Result,2);
   {$ENDIF}
@@ -2587,8 +2594,8 @@ var
 begin
   v:=ReadLRSValueType(s);
   case v of
-  vaInt8: Result:=ReadLRSByte(s);
-  vaInt16: Result:=ReadLRSWord(s);
+  vaInt8: Result:=ReadLRSShortInt(s);
+  vaInt16: Result:=ReadLRSSmallInt(s);
   vaInt32: Result:=ReadLRSInteger(s);
   vaInt64: Result:=ReadLRSInt64(s);
   else
@@ -2693,12 +2700,12 @@ begin
   s.Write(e[0],10);
 end;
 
-procedure WriteLRSShortInt(s: TStream; const i: shortint);
+procedure WriteLRSSmallInt(s: TStream; const i: SmallInt);
 begin
   {$IFDEF FPC_LITTLE_ENDIAN}
   s.Write(i,2);
   {$ELSE}
-  WriteLRSReversedShortInt(s,Word(i));
+  WriteLRSReversedWord(s,Word(i));
   {$ENDIF}
 end;
 
@@ -2806,7 +2813,7 @@ begin
   begin
     b:=byte(vaInt8);
     s.Write(b, 1);
-    b:=Byte(Value);
+    b:=byte(Value);
     s.Write(b, 1);
   end else if (Value >= -32768) and (Value <= 32767) then
   begin
@@ -3243,18 +3250,26 @@ var
   CopyNow: LongInt;
   SourceBuf: PChar;
 begin
-  SourceBuf:=@Buffer;
-  while Count > 0 do
-  begin
-    CopyNow := Count;
-    if CopyNow > FBufSize - FBufPos then
-      CopyNow := FBufSize - FBufPos;
-    Move(SourceBuf^, PChar(FBuffer)[FBufPos], CopyNow);
-    Dec(Count, CopyNow);
-    Inc(FBufPos, CopyNow);
-    SourceBuf:=SourceBuf+CopyNow;
-    if FBufPos = FBufSize then
+  if Count<2*FBufSize then begin
+    // write a small amount of data
+    SourceBuf:=@Buffer;
+    while Count > 0 do
+    begin
+      CopyNow := Count;
+      if CopyNow > FBufSize - FBufPos then
+        CopyNow := FBufSize - FBufPos;
+      Move(SourceBuf^, PChar(FBuffer)[FBufPos], CopyNow);
+      Dec(Count, CopyNow);
+      Inc(FBufPos, CopyNow);
+      SourceBuf:=SourceBuf+CopyNow;
+      if FBufPos = FBufSize then
+        FlushBuffer;
+    end;
+  end else begin
+    // write a big amount of data
+    if FBufPos>0 then
       FlushBuffer;
+    FStream.WriteBuffer(Buffer, Count);
   end;
 end;