I just did an import from Blogspot. It was stunningly seamless. Everything just worked. I had to pick my jaw up off of the floor when it was done. It seemed too good to be true.
And of course it was, but I don't think this problem WP's fault. The images embedded in blog posts stopped working after a while. I poked around in the HTML and discovered the image tags all refer to photos1.blogger.com. My theory is that photos1.blogger.com eventually figured out it was serving images onto pages which were not hosted on blogspot. I imagine it considers this to be stealing bandwidth, which makes perfect sense.
My question is what I can do about it. It seems somebody needs to crawl all the image tags and [a] pull down the image files and [b] rewrite the URLs. I might be able to persuade some web browser to do [a] for me, but that still leaves the URL rewriting. Anybody have any ideas?