A Photo Viewer is a software application designed to display images on a computer or mobile device. It allows users to open, view, and navigate through various image formats, such as JPEG, PNG, and GIF. Many photo viewers also offer basic editing features, like cropping and rotating images, making it easy to enhance photos before sharing or printing. Most operating systems come with a built-in photo viewer, but users can also download third-party options for additional features. Some popular photo viewers include Windows Photo Viewer, IrfanView, and XnView. These applications often provide slideshow capabilities, allowing users to enjoy a collection of images in a continuous format.