If the upload path is set to:
$WAGLOBAL_Images_Folder = "../images/"
it will add the ../ to the paths regardless of the browser that is being used.
it should not make a difference whether you are using IE 6 or 7. Do you have a link where I could see the problem to investigate what is going wrong?
If the image upload is failing with the upload path set to "images/", there is mot likely a permissions error on that directory. It could be set to read only or the permisins do not allow for write access.