Today I just happened to be trying to hotlink an image from ImageShack using the [img] tags, and I had the constant problem of the tags being parsed into the hyperlinks. And then when I looked around for the "insert image" button in the Advanced Reply, I could no longer locate it.
Why has this been disabled? I'm aware of the annoyance of having a dead hotlink, however I liked to hotlink my images from ImageShack instead of using attachments because I can place the images anywhere in my post, which is helpful when someone else is reading my post. Secondly, it's fullsize, so I can scale the image as large as possible without going out of the content boundaries, and then it saves the reader an extra click.
I understand that Dani is trying to make the posts self-contained, but the least that you could do is allow us to reposition the placement of the images that we attach to our posts.