Icon instead of Text

Maybe I am doing something wrong or maybe it is not possible. I wanted to make only two Navigation menu items into icons. Under the navigation menu I placed in the Icon spot the address to the png that I want displayed. I placed the icon png into the base and also into the current templates appropriate image/icon folder. Thinking that I would now clear cache and wala icon would show and the text would disappear. Did not work. So, I took out the text in both the block and the language key and wala....no luck just disappeared, no icon but link remained. The instructions that appear in Boonex Help is really outdated. I know I am going to feel really stupid after someone says: just move this and do this boom. done. Who wants to make me feel like dumbo?

 
Did you actually use a full address?

If so. That's incorrect. Just the name of the icon. Example.  icon.png

 

Yes, I did, all fixed, Thanks Deano