In Contact version 4.2 and above right click then select Settings and Preferences. In the Preferences dialog select the Caching tab. You will see the Universal Media controls.

The Local Universal Media Directory is where the texture files are being cached when the library has not been installed but downloaded incrementally as you navigate worlds which use it.

When the library has actually been completely installed via an installer, or if it is available from a CD or another media, you may specify the path in the Additional Read Only Cache Directories field.

Upon entering another world using Universal Media, the files will be loaded into the world immediately without having to wait for them to download.

To enable your world(s) to use Universal Media, you will need to specify a URN and a URL in the texture URL fields of your Web3D file(s).

When you select a texture category, you'll get a complete URN/URL entry for each texture. This can be copied/pasted into the texture URLs of any Web3D world. For example, the entry generated for a texture named "sign_2.gif" (which is in the "urban" category):

"urn:web3d:media:textures/urban/sign_2.gif",
"http://www.officetowers.com/UniversalMedia/textures/urban/sign_2.gif"

The first entry, a URN (Uniform Resource Name), will be skipped by browsers not able to handle them. If the browser does handle them, however, the media will be fetched off the hard drive. The 2nd entry is a fallback URL where the media can be fetched via Web (from an official Universal Media mirror site).

Note: All versions of Contact above 4.2 support URNs and Universal Media.