Exactly this url (i used http://admin:password@hostname/cgi-bin/snapshot.cgi) gives me a picture BUT (and that is why i don't use it) it takes ages to get the picture back and thus has a high delay. Therefore i'm using a solution like riogrande75 but with a daemon that runs continuously and writes every couple seconds the image to a ramdisk. Through that i have the "current" picture available for anything you can imagine, e.g. Telegram or Fritz!Fon
You don't have to include the #0, i just have 101, 102 etc as room names. And DEE1010B is only possible to be available once on the RS485 bus to my knowledge.