Issue 80 and F3

There are many ways to bring in sprites using CSS but using a background
image is harmful to people with low vision. Providing a simplified
background is critically important to people who experience loss of detail
or become fatigued when working with fine detail. A busy background just
buries the detail of text. Even with sufficient contrast the variable
pattern just confuses the textual content. That is why High Contrast
settings kill background images. The need for high contrast is not the
problem, it is the need for a uniform background.

The critical feature of the CSS background-image is that it identifies its
intended use.  If an author uses background images as background, then the
user or the user's software can remove the image and replace it with a
useful background.  If the author uses background-image for another reason
there is no programmatic way for the user or user software to identify that
image as potentially meaningful.

The nice thing about the Windows High Contrast mode is that it gives you a
full 16M colors to set up your own environment. So, people with photophobia
don't have to suffer with bright colors to get a simplified background.