Take a good look and tell me what you see (in an unusual stylistic move for me, you can click these images to see them full size):
The top image is a menu made up of images. Which means not only does loading the site require loading a bunch of extra jpg, png or gif files, but much more importantly search engines don’t know what they say. To make matters worse, this particular site didn’t even use alt tags*.
Plus if you do click on it to see the full version, you’ll notice the text isn’t even well formed, it’s pixelated and ugly.
The bottom image is the same menu, with a tiny one-pixel-wide image (well, actually two one-pixel-wide images) repeating. The text is just that, text. So search engines can scan it, and see what they say.
The implications of that is you can have your pages’ headings, which should sum up the content of your site pretty well, on every page. Those headings should be written to include your keywords, and you really want those on every page!
And thanks to modern font smoothing on mainstream operating systems, they look a lot nicer.
I cannot fathom why this menu was originally made entirely with graphics. Unless it was just for the roll-over effect, which did nothing but make the text turn orange.
Which it still does, thanks to some really simple CSS.
* Please note, alt tags are actually not tags at all, but attributes of the img (image) tag. I really should adjust and start using the right terminology, but when you’ve been at this for 17 years, well, old habits die hard.