delphi Image控件操作数据库Image

引用这个单元jpeg
procedure TCommMethods.uploadimage(img:TImage);
var
  OpenPictureDialog:TOpenPictureDialog;
  bmp1:TBitmap;
  jpg1:TJpegImage;
  sFileName:string;
begin
   OpenPictureDialog:= TOpenPictureDialog.Create(nil);
   with OpenPictureDialog do
   begin
      if   Execute   then
      begin
        sFileName:=FileName;
        if ExtractFileExt(sFileName)='.bmp'   then
        begin
          bmp1:=TBitmap.Create;
          bmp1.LoadfromFile(sFileName);
          bmp1.Assign(bmp1);
        end;
        if (ExtractFileExt(sFileName) ='.jpg') or  (ExtractFileExt(sFileName)='.jpeg') then
        begin
            bmp1:=TBitmap.Create;
            jpg1:=TJpegImage.Create;
            jpg1.LoadfromFile(sFileName);
            bmp1.Assign(jpg1);
        end;
        img.Picture.Assign(bmp1);
      end;
   end;
end;
用于插入数据库
function  TCommMethods.retrunchannelimageid(img:Timage):string;
var jpg1:TJpegImage;
begin
  try
    jpg1:=TJpegImage.Create;
    jpg1.Assign(img.Picture.Bitmap);
    with DM.qrypublic do
    begin
      Close;
&