Netscape 6.2 <img alt> problem!

I am using Netscape 6.2. Within my tag I am using the ‘alt’ attribute, but it is not showing the message. Now, I do know it works in other browsers, but not in my Netscape 6.2 version.

Does anybody know what the scoop on this is?

Example:
where when I put my mouse over the image, no message “Bob” is showing.

Thanks!
Jim