ThinVNC allows you to modify the web interface and tailor it to your branding scheme.
Customizing the application logo and other image files can be very simple, once it only requires you to have the new image file and tell the application where it is located.
Customizing the structure and style of the application may be a little bit more complex. These kind of customizations have to be done at a programming level (HTML and CSS).
Read also how to protect the customized web files in the Files Location topic.