type
  Long      = Longint;     // Integer

 TBLOb = record
   GetSegment: function(Handle: Pointer; Buffer: PChar; MaxLength: Word; var ReadLength: Word): WordBool; cdecl;
   Handle: Pointer; // BLOb handle
   SegCount, // Number of BLOb segments
   MaxSegLength, // Max length of BLOb segment
   TotalLength: Long; // Total BLOb length
   PutSegment: procedure(Handle: Pointer; Buffer: PChar; Length: Word); cdecl;
   Seek: function(Handle: Pointer; mode :Word; offset : Long): Long; cdecl; // а я знаю входные параметры...
 end;  

var
 iStream: TMemoryStream;

   try
     iStream.WriteBuffer(i^, size);   //размер верный
     iStream.Position:=0;
     iStream.SaveToFile('d:\1\fl.jpg');  // но в файл пишет с какими то пробелами что ли
     iStream.Position:=0;
     try
     jp.LoadFromStream(iStream);  // тут падает  
     //Access violation at address 0000000004E07B0E in module 'bl.dll'. Read of address FFFFFFFFFFFFFFFF
  except

with oBLOb do PutSegment(Handle, Buffer, ReadLength);

 TBLOb = record
   GetSegment: function(Handle: Pointer; Buffer: PAnsiChar; MaxLength: Word; var ReadLength: Word): WordBool; cdecl;
   Handle: Pointer; // BLOb handle
   SegCount, // Number of BLOb segments
   MaxSegLength, // Max length of BLOb segment
   TotalLength: Long; // Total BLOb length
   PutSegment: procedure(Handle: Pointer; Buffer: PAnsiChar; Length: Word); cdecl;
   Seek: function(Handle: Pointer; mode :Word; offset : Long): Long; cdecl; 
 end;


const
  MaxBLObPutLength = 80;
  MaxBufSize = 32768;

//  fast resize  /////////////////////////////////////////////
//////////////////////////////////////////////////////////////
//x - x resolution                                          //
//y - y resolution                                          //
//iBlob - input BLOB                                        //
//oBlob - output BLOB                                       //
//////////////////////////////////////////////////////////////

procedure ResizeImageXY(var x: integer; var y: integer; var iBLOb: TBLOb; var oBLOb: TBLOb); cdecl; export;
var
 iBuf, buffer: PAnsiChar;
 ReadLength, StreamSize, BufSize: integer;
 stream: TStream;
begin
  with iBLOb do if (not Assigned(Handle)) or (TotalLength = 0) then Exit;
  Stream:=TMemoryStream.Create;
  try
    GetMem(iBuf, iBlob.TotalLength+1);
    try
      FillBuffer(iBLOb, iBuf, iBlob.TotalLength, ReadLength);
      ConvImageXY(x, y, ibuf, ReadLength, Stream);
      //procedure ConvImageXY(x, y:integer; i: PAnsiChar; size: integer; var o: TStream);
    finally
      FreeMem(iBuf);
    end;
    StreamSize := Stream.Size;
    Stream.Position:=0;
    if StreamSize > MaxBufSize then BufSize := MaxBufSize else BufSize := StreamSize;
    GetMem(Buffer, BufSize);
    try
      if StreamSize > BufSize then ReadLength := BufSize else ReadLength := StreamSize;
      Stream.ReadBuffer(Buffer^, ReadLength);
      with oBLOb do PutSegment(Handle, Buffer, ReadLength);   /// здесь вылетает
      Dec(StreamSize, ReadLength);
    finally
        FreeMem(Buffer, BufSize);
    end;
  finally
   Stream.Free;
  end;
end;