Images serve a crucial role in biological research and teaching. The WholeSlide app by Richard Stoner provides an elegant solution to the question, “How can I best view large (1 gigapixel and greater) images on my tablet device?” The app allows users to easily access and explore image datasets that are hosted online. A small number of datasets come preloaded with the app, including the Allen Reference Brain, images from Brainmaps.org, WormAtlas, and Zebrafinch Atlas; however, users can also upload their own web-based datasets. When viewing individual images, users can zoom in/out with their fingers, they can opt to view the metadata for each image (although most of the preloaded images are not well-annotated), and they can adjust the brightness, contrast, and color channels of the image.