A zooming rollover combines a rollover menu with zooming images that temporarily reveal high-resolution visual details and may serve as previews of available information.

The zooming rollover concept was created, explored, and prototyped by Jonathan Helfman for AT&T Labs-Research as part of his work studying the application and organization of visual representations (see the Mandala page).

In this case, the zooming rollover starts with a menu of thumbnail images from bookmarked personal home pages. Rolling the cursor over a thumbnail causes a high-resolution copy of the thumbnail to zoom forward while dissolving on and off, temporarily revealing visual details that may have been obscured when the image was scaled down to a thumbnail. Textual details, such as the person's name, may also be included in the high-resolution image. Selecting the thumbnail or the zooming image loads the bookmarked page in a web browser.

Zooming is a familiar filmmaking technique in which the camera lens is adjusted to change the field of view from a long shot to a close-up in a single smooth, continuous motion. Zooming has the effect of first setting context and then revealing details. The smooth continuity of the zoom allows viewers to remember the context while appreciating the details.

While zooming is effective in films, it seems less successful when used as a technique for navigating in virtual worlds, where the hierarchical relationship of context to detail is less clear.

Rollover menus may be a more appropriate use of zooming than virtual world navigation because the hierarchical relationship of context to details is usually quite clear in a menu. Also, viewers experience very little loss of context with zooming rollovers because the underlying image menu does not move and remains visible in all but a few frames of the zoom.