Why do logo's, pictures, buttons, etc. not show up correctly? when is there is normally a button/picture with a link on it, the picture doesn't show up, just the plain old text.

flash and java games work fine on mozilla, but on the rest of every other website, pictures with links on them don't show up. for example, on the google homepage, there logo doesn't show up, its just a blank white space with a search box under it.