search engine dilema - can't find answer to these?

Hi:

Does anyone know the answer to these? Help would be appreciated.

Regarding search engines following links -

1. do they follow links imbedded in an image map?

2. do they follow links embedded in dhtml dropdown menus?

3. do they follow links embedded in a dropdown box?

4. when an image is used for a link, do they check the size and validity of the image as whether pertinent to the link?

I have looked for the answers but couldn't get any definitive ones.

Thanks.

Bud