preloading images

[moondance]

i've just been browsing this forum and i've got myself quite confused over the concept of preloading images.

Once an image has been preloaded, is that the only time you need to preload it? for instance, if you have an image that appears on every page like a background, do you need to preload it on every page, or just the first page?

[Khalid Ali]

In essence every thing is limitied to a document( a page),so images loaded in a page1 are only for page1.

[AdamGundry]

If the browser caches images normally, once an image has displayed once it should be stored for the remainder of the session at least, regardless of which page calls it.

I think what Khalid means is that you can only display with JS an image preloaded with JS on the same page. Or am I wrong?

Adam