Vista and thumbnail options

When opening pics through our server, one of our computers (the only one with bloody Vista) has either lost or never had an option for thumbnail viewing, whichever view is chosen we get a generic picture. There is no actual ‘thumbnail’ choice on the drop down list as with XP, is this normal with Vista? Sometimes the thumbnails flash up but quickly revert to the picture. I have been browsing forums all morning and tried everything of which I am capable. Unchecking the “always select icons” box is not an option as this was already unchecked.