Please stand by, I'm trying to see how Zooomr works with Blogger.
Here's a picture of part of one of my bookshelves:
OK, looks like Blogger really wants you to limit things to sizes that work with their layout. I guess I'll be sticking to small sizes that you can blow up by clicking on.
Now, to see why Zooomr doesn't store the original size... Ah, OK once you have a Pro account, it looks like you get to keep the original size, too.
Also, it would be ungenerous of me to not point out that Zooomr is giving away free Pro accounts for something as simple as posting a pic like this on your blog.