I really don't like this forum
This has happened to me so many times, and I don't know why I continue doing it. I write long posts, and then add pictures. After I add the fourth picture the thing freezes, and it says Inserting image... for a long time. The only thing I can do is reload the page, but my long post would be all gone. :/ There should be a way to close that Inserting image... box.
It really has something against this picture. It doesn't add it from a link or when I save it to my computer.
If you are using Internet Explorer, try to reset your browser settings. Maybe something you loaded or added in the past messed up your editing abilities. I had an issue with facebook where I couldn't use the next button or tag a photo until I reset my browser. Could be an add-on that is causing problems.
Are you up to date with your antivirus software? Could be a virus also. Just a thought.