Why my Image or Picture button does not show the image?

 I have put the following code in my 'when-new-Block-Instance' 

declare
     it_id  item;
begin
     it_id := find_item('PB_ACCT_NAME_SEARCH_CONTACTS');
     set_item_property(it_id, ICON_NAME, 'E:\DevSuiteHome_1\bpmod61\ICONS\MEMZOOM1.bmp') ;
end; 

P.S. I also have tried  :-

set_item_property(it_id, ICON_NAME, 'E:\DevSuiteHome_1\bpmod61\ICONS\MEMZOOM1') ;

and

set_item_property(it_id, ICON_NAME, 'MEMZOOM1') ;

In the Puch Buttom property, I have :-

Iconic = Yes

Icon filename = MEMZOOM1

Default button = No

I still cannot see the inage. This image comes with Oracle Install itself. I also tried the same with another .gif file too. Still no image shows.