I know how to attach a single picture using the "picture URL" box, but is there a way to attach multiple pictures, not as links but as pictures that show up in the message body?  If I put spaces between the URLs in the "picture URL" box, will that work?  Thanks in advance.

You have to first publish the multiple pics to a web page and then you can put the url to that page in your post as the pic url.  I am pretty sure that is the only way.