hereis the link: http://eec.github.com/book/
The pictures jump to the second line after 2 picture is showed up.
I know float:left could solve the problem instantly, but I just don’t understand why the pictures are arranged like this?
Who can tell me why? Thanks ahead!

The next 6 links (after the first 2) don’t have whitespace between them, so they can’t wrap.
If it helps, images behave as letters in words, so these 6 images basically are in the same “word”. The browser doesn’t break inside words.