If you're talking about the official NDS Opera Browser.....it's just like that. It didn't actually freeze, it's just figuring out the page structure and background colors. Eventually, if you wait long enough, the page will sort of pop and the general page structure will appear. It will then continue to load the rest of the images.
As long as you see that little symbol animating in the top-right corner, the browser itself didn't lock-up.