Start by zipping the files up into a ".zip" compressed folder, and then use the "Submit a File" link in the "Resources" box on lower left of page.
Follow the prompts to upload to the proper library using the following guideline:
If the files are ".ico" (Windows icon format) - upload to the "Misc. Icons" library.
If the files are ".png" image format - upload to the "ObjectDock" library.
Make sure the artwork falls within the guidelines and rules, both links can be found in the interface text during upload procedure.