TMemoryStream이 함수로  해보심이 어떠하실런지..

var
    mem: TMemoryStream;
    bjpg: TJPEGImage;
    Image1 : TImage;
Begin

  mem    := TMemoryStream.Create;
  bjpg   := TJPEGImage.Create;
  Image1 := TImage.Create(Application);

  Image1.Picture.LoadFromFile(xOpenPictureDialog.FileName);
  bjpg.Assign(Image1.Picture);

  bjpg.SaveToStream(mem);
  mem.Position := 0;

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ParamByName('pimage').LoadFromStream(mem,ftblob);

이렇게 함 해보세요...

즐프 ~

참고하세요..
BItmap이면 JPEG로 변환해서 저장합니다.
반대로 Bitmap 을 넣고싶다면 변환부분만 반대로 처리하면 되겠지만
JPEG 에 비해 사이즈가 너무 크니 좀 무겁다는 감이 들겁니다..

var
     BitImage  : TBitmap;
     JpegImage : TJPEGImage;
     MS: TMemoryStream;
begin
     with Query_TEMP do
     begin
          //========================================================= Insert
          Close;
          SQL.Clear;
          SQL.Add('INSERT INTO CCA0051T (EMPECD, SIMAGE, CRTEMP, CRTTIM, UPDEMP, UPDTIM )');
          SQL.Add('VALUES (:EMPECD, :SIMAGE, :CRTEMP, :CRTTIM, :UPDEMP, :UPDTIM)');

          ParamByName( 'EMPECD' ).AsString := dxMemData_MainMEMBER.AsString + ' ';

          if Image_Open.Picture.Graphic is TBitmap then
          begin //===================================================== BMP SAVE
               BitImage   := TBitmap.Create;
               MS         := TMemoryStream.Create;

               MS.Position := 0;
               if Image_Open.Picture.Graphic = nil then
               begin
                    ParamByName( 'SIMAGE' ).Assign( Image_Open.Picture.Bitmap );
               end else begin
                    BitImage.Assign( Image_Open.Picture.Bitmap );
                    BitImage.SaveToStream( MS );
                    ParamByName( 'SIMAGE' ).LoadFromStream( MS, ftBlob );
               end;
               BitImage.Destroy;
          end else begin //=========================================== JPEG SAVE
               JpegImage   := TJPEGImage.Create;
               MS         := TMemoryStream.Create;

               MS.Position := 0;
               if Image_Open.Picture.Graphic = nil then
               begin
                    ParamByName( 'SIMAGE' ).Assign( Image_Open.Picture.Bitmap );
               end else begin
                    JPEGImage.Assign( Image_Open.Picture.Graphic );
                    JPEGImage.SaveToStream( MS );
                    ParamByName( 'SIMAGE' ).LoadFromStream( MS, ftBlob );
               end;
               JPEGImage.Destroy;
          end;

          ParamByName( 'CRTEMP' ).AsString := gs_UseEmpCd;
          ParamByName( 'CRTTIM' ).AsString := FormatDateTime( 'YYYYMMDDHHMM', now );
          ParamByName( 'UPDEMP' ).AsString := gs_UseEmpCd;
          ParamByName( 'UPDTIM' ).AsString := FormatDateTime( 'YYYYMMDDHHMM', now );

          ExecSQL;

          MS.Destroy;
     end;