It won't let me. It adds some crappy code to the link text.
Trust me. I did a direct copy and paste from MSN. There aren't any spaces in the IMG tags or anything . I've even tried to put it in through html
<img src="http://groups.msn.com/_Secure/0NwD1HRYTFf8olSsnqjtNpHBoi4Jd4z73v4ej6yyApvsBYvWKr 877XZvXOApW94HQxG6qnpMjQeu1RYH8n0aN6Q/C5Front2.JPG"
Nothing works. I have the same problem on 2 other boards too. I don't know why.