Many times customers want to customize the login screen for webmail. This could be adding a custom logo, a unique page title, a branded background image and more. All of this is possible right from within the interface. It's worth noting, however, that just like almost any other setting, customizations can be managed from the top, down: System Administrator >> Domain Administrator >> User (to a lesser extent).
NOTE: For System Administrators, custom logos are set to a max width of 200px and a max height of 100px; for Domain Administrators, custom logos are set to a max height of 225px and a max width of 100%.
System Administrator Customization
Just as with Domain Defaults and User Defaults, System Administrators can set a default customization for the webmail login page. Tthen individual Domain Administrators can change that default customization to better fit their individual organizations. For example, below is a screenshot of the customization options that the System Administrator can set. These are located in the General settings area when logged in as a system administrator.

Administrators can also add custom pages that are called when someone logs out of webmail, and even change the URL used for the online help documentation to their own helpdesk or even a helpdesk contact page.

As you can see, there's a default Logo Image, Custom Title Text (the text that appears on the browser tab) and Custom Login Text (the text that can appear on the login page itself). In addition, the background image on the page can be changed from a default image to a custom image or even a flat color.
On the login page, shown below, a new logo image was added, the background was changed to a light gray, the login text was changed and the logout URL was also changed to send people to the SmarterTools website once they log out of webmail. This, then, forms the default template for any new domains that are added to SmarterMail.
Domain Administrator Customization
Now the above may be good enough for most webmail users. However, certain companies may want to customize their logins a bit more, tailoring them to match their brand. That's where the Domain Administrator comes in. A Domain Administrator can log in and essentially overwrite many of the customizations implemented by the System Administrator. The one thing they don't have control over is the background -- the rest can be fully customized to the business. This is accomplished in the Domain's Settings -> General page.
So, a Domain Administrator can add in a company logo, add in custom Login Text, change the Logout URL and even customize the Help URL so that company users go to the company's help documentation or support portal if there are issues. With these changes made, the new webmail login page looks like this:
As you can see, the ability to customize the login page for SmarterMail can make a huge difference, personalizing the page and branding it for the business.
A Quick Note on "White Labeling"
The above customization options can go a long way to essentially "white labeling" the webmail login page as well as the pages outside of the SmarterMail interface that customers may access. For web hosting companies, ISPs or service providers who want to offer SmarterMail to their customers, with as little SmarterTools branding as possible, customizing the webmail login page with company-specific language for the Login Text and Title Text, along with your own custom logo essentially brands your mail offering to you. And changing the Custom Help URL and text to point to your own help docs or even your help desk pushes your customers to your support options. All of these get you very, very close to that goal of a white labeled email solution.