AltaVista, a business of Overture Services, Inc., has announced that it has significantly expanded its multimedia index to more than 550 million. AltaVista's expanded multimedia index catalogs more than 540 million high-quality image files and approximately 11 million video and audio files, including formats such as MP3 and MPEG. Also included are hundreds of millions of files published in countries around the world. To improve searching capabilities AltaVista added a new refinement feature to its image index that enables consumers to customize searches by dimension The index now places greater emphasis on providing searches by file quality, including customized searches for larger image files and superior downloadable audio and video content. The enhanced index also includes professional image content from providers of digital images worldwide. Before the most recent update, AltaVista's index included 400 million media files.