The Photos app in Windows 8 is fine for viewing your photos, but you can't do a whole lot more with it than that. In Windows 8.1, Microsoft beefed up the app with a host of editing controls, so you can tweak your photos all you like. To give it a whirl, click on the Start screen tile for the Photos app. Open a photo from your any folder, then right-click on the photo to display the app bar. You can rotate it or crop it by selecting the appropriate buttons.
To do more intensive work, select the 'Edit' button, and up pops a host of options for modifying your shot. You can choose one of the photo thumbnails on the right to apply an auto fix to your photo. Alternately, you can select one of the other settings on the left (including Basic fixes, Light, Color, and Effects) to manually fine-tune your photo. When you're done, right-click on the screen to display the app bar again. You can now save a copy of the edited photo, update the original, or cancel your changes.