Technical question

Hello everyone.

I'm trying to write down some pages in HTML to make my stuff available on
the www. I've come up with a quite good graphic, even if I don't use those
helly frames nor Java, because (i) I don't know how to use them (ii) I have
when I have to wait downloading. My problem now is that I have some gif
images my IE perfectly shows, but they can't be seen with NNavigator. Since
I made them with WinPaint I was wondering if the problem could be generated
by that programme. Indeed I imported my gifs on HTML Construction Set, I
saved them there and they work... but they loose some characteristics.
Whatta do?

Luca