procedure Open;
begin
  QrySelect.QuerySQL := 'select image from table where id=1';
  QrySelect.Cached := true;
  QrySelect.Active := true;
end;

procedure LoadImage(filename : string);
begin
  (QrySelect.FieldByName('image') as TBlobField).LoadFromFile(filename);
end;

procedure Save;
begin
  QryUpdate.QuerySQL := 'update table set image = :image where id=1';
  QryUpdate.Cached := false;
  QryUpdate.ParamValue[QryUpdate.GetParamNumber('image')] := QrySelect.Fields( 0 ).Value;
QryUpdate.ExecuteSQL;
end;