The built-in Windows Photo Viewer offers a great way to view your photographs and images, especially when you use its Slide Show feature. In Windows 10, if you find that your Windows Photo Viewer slide show is not working the way you want it to, with only a part of the photograph being displayed, then you may try this solution. This problem could occur if DPI virtualization is being used.
Windows Photo Viewer slide show not working
To resolve this issue, save all your files and work first. Once you have done that, right-click on the Windows desktop and select Screen resolution. The Screen Resolution Control Panel applet will open. Here, click on Make text and other items larger or smaller.
Now, in the Windows 8 Custom sizing options dialog box, click on Custom sizing options. In the settings box which opens, select the Use Windows XP style scaling check box. Click OK.
You will be asked to save your work and sign out. Click on Sign out now. Restart your Windows 8 computer and sign back in. The issue should have been resolved.
Hope this helps.