I just looked at your site and I must admit that it looks very nice. However, I was viewing it with both a 1280px X 800px screen resolution and a 1280px X 1024px resolution. IMHO, your content is way too wide for most people as most users still use 1024px X 768px (the most popular). Even with the screens I was viewing your site on, I got scroll bars at the bottom. I just thought I would let you know that.
As for your question about the buttons you created for the top block (I assume you were talking about the 4 buttons that say Forum Rules to About Us), they should show up correctly on fairly low resolutions despite the fact that they are very large images. However, it seems that they aren't showing correctly in the block. If you would please post the code you are using in that block, one of us will gladly check it on one of our test sites it to make sure it is formatted correctly. Just post the code here using the [ code ] tags and one of us will take a look at it.