That is a good question, I don't think that they will because search engines normally avoid small words like if, it, and, the, etc. I'm not positively sure about links though but i was have that it would be set along the same principles.
This is not quite what you are asking, but I have an image linked to a single period (.) on a PR6 site that has not been indexed and the link has been present for about 7 years, ie the image does not show up in an image search on google.
Yes they do follow the links, maybe the image doesn't show up because it is not relvant to the search
I know one site that is PR 8 because it is linked to solely from a PR 9 site with 2 letters (the language code). I am linked to from the PR 8 sites, so hopefully I will get at least PR 7 on the next update. By the way, all the translations of this page are PR 8 and are linked to with only the two letter language code. So, I have to say firmly that a one or two letter link is just as good as any other.
Could be, since it's only an image and not a page with an image, this is probably a different situation. I've tried searching in images for a combination of the sitename and the image name but no results. For a good test, though, the link should actually go to a page with text on it.