The Image link Issue
When creating a link for an image in one of your posts, upon saving or updating your post, WordPress defaults the link to the image source. Annoying? Yes very much.
Apparently the issue has been resolved though has yet to make it into a stable build: Source.
This WordPress thread highlights the issue in greater depth:
Now when you upload an image it puts the url of the image in the link box (to where it is on your own site) and when you attempt to replace that with any other link, say, to the source of the image offsite) it erases it and puts the original.
A temporary solution until wordpress gets updated to version 3 is to link your images as normal in your post, then use the HTML editor to edit the image source and remove the
<a rel="attachment wp-att-3434" href
of the image and replace it with
Hopefully that tides you over until the bug is finally fixed.