A little help with CSS

I have this website for a company and they told me that in IE8 the thumbnails from iPhone are outside and in Firefox are inside.
Can someone tell me what to do in css to have the same result in both browsers?

Now, with one thumbnail it’s ok, but I have to put 4 on each line. In Firefox works, but in IE I have only 2 on each line. You can see here.

Try changing .tabx ul to the following

.tabx ul {
margin:23px 0 0 115px;
padding-left: 40px;

Thank you for help. I just saw that the menu, under the button, each item goes too big on hover in IE.

You should set the width of .tabx ul li to 70px instead of 50px (seeing as the images therein are 70px wide) and then set the right margin to 5px instead of 25px.