Here's a sample request for smugmug.images.get:

http://api.smugmug.com/hack/rest/1.1.1/?method=smugmug.images.get&SessionID=8fsda fsljkaer&AlbumID=27

Here's a sample response to a smugmug.images.get call:

<?xml version="1.0" encoding="utf-8" ?>
<rsp stat="ok">
 <method>smugmug.images.get</method>
 <Images>
  <Image id="17833"/>
  <Image id="17832"/>
 </Images>
</rsp>

Here's a sample error response to a smugmug.images.get call:

<?xml version="1.0" encoding="utf-8" ?>
<rsp stat="fail">
 <err code="4" msg="invalid user" />
</rsp>