thumbnails not displaying correctly in firefox

Happens in firefox on both Mac and PC

This is because your links and images are inside a span element. If you remove that, it fixes the problem (at least for me).

Ok I fixed it by adding this to the stylesheet:

.press_logos div span {
    display: inline-block;
    vertical-align: middle;  /* vertical alignment of the inline element */
    max-width: 100%;
}