If you\'re adding a post every few seconds, then you\'d really spam your database. Adding an attachment (which is some type of post), is not really different, but more appreciated. Take a look at these functions.

Just my 2 cents: I\'d just display it according to the url, not download, save and add a post with lots of unnecessary data. If you need to save it, you\'re better off with simply saving it in some custom folder and not use the wp engine at this point. You could create date and/or time based folders and use the folder name as img caption or such.