Solved when:
procedure TForm2.Grid_DettaglioGiornoCellClick(Column: TColumn);
var
MioStream: TStream;
IdNota: integer;
begin
IdNota:=Grid_DettaglioGiorno.DataSource.DataSet.FieldByName('IdNota').AsInteger;
Q_Generica.SQL.Text:='Select Immagine FROM T_Scontrini Where IdNota=' + IntToStr(IdNota) + ';';
Q_Generica.Open;
if not Q_Generica.EOF then
begin
Q_Generica.First;
//MioStream := TStream.Create;
try
if not Q_Generica.FieldByName('Immagine').IsNull then
begin
//TBlobField(Q_Generica.FieldByName('Immagine')).SaveToStream(MioStream);
MioStream := Q_Generica.CreateBlobStream(Q_Generica.FieldByName('Immagine'),bmRead);
MioStream.Position := 0;
Img_Modifica.Picture.LoadFromStream(MioStream);
end
else
begin
Img_Modifica.Picture.Clear;
end;
finally
MioStream.Free;
end;
end
else
begin
Img_Modifica.Picture.Clear;
end;
Q_Generica.Close;
end;