I need to find somewhere that has a tutorial on creating an image map, which when you mouse over certain areas, a second image beneath it would change to tell you what you are pointing at.
for example, a picture of a skeleton, that when you mouse over the "tibia" a second image would display tibia.
There are two ways I can think of to do this.
1. Use show/hide layers onMouseOver to display an image over an area of the image map.
2. Use the ALT tag to display a piece of text when the mouse is rolled over it.
I've been working on something kinda like that but what I did (i don't think you could do this b/c your idea sounds a little more complicated :) ) is I seperated each part into a seperate image and put it in a table. That way it loads faster and the mouse over effect is a lot easier to handle.
That is the way to do it. In fact, using large images for image maps is not a good way to go unless it's the only way to achieve a look you want. It is good practice to carve up images and put them into tables. The best possible way is to try and replace parts of the images with html. In other words, match colors in some cells to look like the image, if you can. Also, use html for text when you can.