I tried searching for this but "alt" is too common a word.
I'm not sure what I should set as the value of the alt attribute for decorational images. alt="" or alt="foo icon"?
On the one hand, it would be annoying for screen readers to read "foo icon" all the time, especially when it says "foo" in plain text right next to it anyway. Even for people with sight, it would be silly if it said "foo icon foo".
On the other hand, during the time that I experimented surfing with images disabled, I found that a lot of images had no alt text, and when I saw a blank box I really wanted to know what the image that I knew was supposed to be there was.
Or maybe I should put alt="[image: foo icon]", in case the majority of text-only browsers don't indicate that a piece of text is actually an image?
I can't weigh the benefits and consequences of each path on my own, so I'm taking it to you, the experts.
If this topic is just highly debatable, a matter of personal opinion, I will decide to describe the exact purposes of decorational images (alt="foo icon").
Also, what is the difference in CSS between ex units and em units? As far as I know em units are the size of capital ems and ex units are the size of lowercase "x"s.
Another CSS question: How come different elements are rendered in different sizes if their specified width/height are exactly the same? Really I've only seen pages in Firefox 2 and IE 6.
Now an HTML question: How can I make the browser use the tags I put in the title/alt attributes of an image? It displays the greater than sign I put literally.
EDIT: Unanswered questions:
Link to an icon with rel="shortcut icon" and rel="icon" or just rel="shortcut icon"?
Sometimes JPEGs are smaller than PNGs; Save all images as PNGs anyway, for consistency?