I'll mention as well, I really like to be able to copy/paste images into the blog post. Using the uploader would mean that I have to independently save the images prior to uploading them, but sometimes these images are just going to be quick screengrabs in the copy/paste buffer, instead of image files to select.
Perhaps even giving the image uploader dialog the option to select a file from the copy/paste buffer instead of selecting a file in the filesystem would be the solution?