The only way that you can check is with access to the server logs. I don't know if Bravenet give you those with the paid service, they certainly don't with the free.

Having a Pro account does not necessarily mean remote loading (inline linking, hot linking, etc..) is allowed. Check your Account Manager for a configuration item that allows you to disable linking. My paid hosting is not with Bravenet, but I can enable/disable remote linking as I see fit, from my User Manager. Bravenet may have the same capability. If they can disable it for free sites, they can disable it for paid sites.

Here is the most popular way if you have some skill as a webmaster. Paid accounts on Bravenet, which I have, allow the creation of an .htaccess file. Below is a Google search where you can find instructions on how to create code in a text editor that will block the remote loading of images. Do a search on Google for
htaccess images bandwidth. It seems none of the major search engines will allow searching for specific jpeg or gif file names. They have that capability, but are blocking it for some reason. You can do an image search on Google for the domain name, but that's it.

Jim,

If you use the stats we provide (awstats) it will show you if people are using your bandwidth.

To turn it on, click 'enable stats' in your website manger.

Once they have been enabled for a period of time you will be able to check your stats to see where your hits are coming from. You can find your hits from other sites by clicking 'Referring sites' found under the title 'Referrers:' from there you will see a list of sites, the ones that have lots of 'hits' but little 'pages' means there are linking to your files. So if you see 500 in the hits column but only 5 in the pages column that is a good sign that they are using your bandwidth.

If you find you are having a problem you can then use the .htaccess file like mentioned above.
http://en.wikipedia.org/wiki/Htaccess

Courtnie