In order to activate the Thumbnails option, what mode must the viewer be in?

To activate the Thumbnails option, the viewer must be in Image mode. This mode is designed to display visual content, allowing users to engage with images more effectively. In Image mode, the software can present thumbnails that provide a miniature preview of the full-sized images, making it easier for users to navigate through various visual files at a glance.

This functionality is particularly useful in contexts where users need to quickly browse through a collection of images, as it enhances the user experience by allowing for immediate visual assessment. The other modes may focus on text or presentation formats that do not lend themselves to thumbnail previews of images, hence they do not support this feature.