Question: **Scenario:** In an e-commerce system, a helpdesk user should be able to "impersonate" or "log on as" a specific customer (from the web-based administration site) so that he can support the customer first-hand - eg. when the Customer is on the phone.

Additional clarification: There is no need to keep track of the original authentication context. We simply need to provide a "Log on as" button that will log on as the customer without the helpdesk user needing to know the password.

Any ideas how this scenario could be implemented using regular ASP.NET Forms Authentication?

Answer: 
Save the information about file to MySQL, and save the last time the image was viewed - can be done via some script that would be altered everytime the image is being used.. and check the database for images not used for 30 days, delete them..
As a user,When I upload the image to a server(assuming I want to use it later) and leave the site, I don't expect it to be deleted if I am a registered user.

I would prefer it to be there in my acct until I come back.I would suggest thinking in those lines and implementing a solution to save the users' images if possible.