On the settings page, you can change which domains are used with the uploader. You can get to the settigs page by first logging in, clicking on your username for the dropdown menu and clicking "settings". Alternatively, you can access them from here.
To add a domain: Go to the "Domain Selection" section of the settings page, click on the drop down menu to the left of the blue "Add" button and select which one of our domains you want to use. Some domains go well with a wildcard at the beginning, so to add one, click on the text box next to the drop down menu and input anything you want. Domains can only use alpha-numeric characters with the exception of underscores and dashes. Once you are satisfied with your selection, click the "Add" button.
If you want domains to be randomized each time you take a screenshot, simply add more than one domain.To remove a domain: Go to the "Domain Selection" section of the settings page, find which domain you want to remove and click the [remove] button which resides next to the domain. The domain will be removed.