So, as a rough yardstick, keep the aggregate page size less than 30k . Another important point to note is that each file on the page requires a separate HTTP request to the server. Yes, I'm talking of the ALT text attribute of the IMG tag. Do not forget to provide an Alternate Text for each image that you use for navigation. Though not obviously apparent, ALT text can help such users immensely.
Modern browsers offer users a choice to turn off images.
This gives an idea of how troublesome the unwanted images could be. It is no use making your site a masterpiece of art if users cannot navigate around it - even after they reach the main page, they have no clue as to how to go where they want to go. Especially common, is a kind of navigation that some people call Mystery Meat Navigation . That means, that unless your mouse moves over an image, you have no idea where that link might take you. Only when the mouse hovers do you see the actual link.