How can i save data in BLOB through Form 6.0

Picture data is not inserting through Form 6.0. Actually in my database in BLOB filed I wast to store signatures.
on command button Browse my code is :

Declare
filename varchar2(200);
Begin
filename:=get_file_name('c:\pict','*.tiff');
read_image_file(filename,'TIFF','PIC');
end;


When i am saving record message display "One record applied and saved successfully" But when i am querying the record (F8). then Picture Data is not showing in BLOB filed. when i am using DBMS_LOB.GETLENGTH(pic) then length is showing zero (0). it means data is not saving in BLOB filed. How can i save data in BLOB filed through From 6.0.

Thanks