Photos

The Photos app lets you view, edit, manage, and share photos, other images, and videos stored on your PC, removable storage devices, your phone, OneDrive, and, optionally, Apple iCloud.

Defaults
Photos is the default in-box app for image files--including popular formats like .bmp, .gif, .heic, .jpg, .png, .raw, and many others--in Windows 11. It works well in this regard and offers a wide variety of image viewing, editing, and management functionality. Oddly, there are three discrete experiences, each of which appears in its own app window:

Photo viewer. When you open an image file from the Photos app, File Explorer, or the Desktop, the app's photo viewer window appears to display the image.

Photo browser. When you open the Photos app directly from Start or elsewhere, its full app experience appears. This window includes a navigation pane and a Gallery view with thumbnails of your photos, sources. The navigation pane is configured with links to Gallery, Favorites, OneDrive, iCloud Photos, and This PC views, plus a collapsible overview of your OneDrive storage and its phone integration capabilities. And there is an "Import" button for copying photos from a phone or other device connected to the PC via USB.

Photo editor. If you choose to edit a photo from the photo viewer or main Photos app window, the editor experience appears. If you do this from the photo viewer, this experience replaces the viewer experience in the same window. If you do this from the main Photos app, the editor experience appears in its own window.

By default, Photos is configured to use a Dark app theme across each of its experiences and windows, even if you've configured Windows 11 to use a Light app theme.

Also, the capabilities provided by Photos can vary depending on your PC. Those with a Copilot+ PC get additional functionality that uses the on-device local AI models provided by the platform in the main Photos app and the Photo editor experience. Features unique to Copilot+ PCs are highlighted as needed throughout the chapter.
Customize
You customize some Photos features directly in the app and with the in-app settings page. But its file associations are configured in the Windows 11 Settings app or, on a case-by-case basis, when you open an image file in File Explorer.
Photos settings
To access this app's settings page, open Photos and click the "Settings" (gear) icon in the top right of the window.

Most of this is fairly obvious, but you should disable "Show iCloud Photos" if you don't use an iPhone or have photos stored in Apple's iCloud storage service. If you will use Photos to manage your photo collection, you should also consider changing "Enable Location Based Features" to "On."

Gallery is the default view and it commingles photos, other images, and videos from multiple sources--OneDrive cloud storage, your iCloud Photos collection (if available), and your local PC--in into a single "River" layout by default...