Featured image for archive and category pages

Wow I have read a ton of confusing stuff for a php deficient web designer. I have a custom header for every post using the featured image function in the twenty ten theme and the twenty ten advanced header plug-in solved the problem of getting the default twenty ten image for my category pages but still getting the twenty ten default image for my tag pages. Cant seem to find a plug in for this and why does the image have to change for category and tag pages why doesnt it use the featured image for all. So confused!
This gives featured image .. http://www.broomeandthekimberley.com.au/2011/03/in-and-around-broome/

This gives stretched featured image using advanced header plug in
http://www.broomeandthekimberley.com.au/category/blog/in-and-around-broome/
AND THIS http://www.broomeandthekimberley.com.au/tag/anastasias-pool/
gives the default twenty ten header image.