In Windows 8.1 and Windows RT 8.1, there are a couple of new places where you can see your favourite photos: Start and the lock screen.
You can use your own photos, or download some from the Personalisation Gallery. To learn more about personalising your PC, see Personalize your PC and Getting started with themes.
If you want to use a picture from the Personalisation Gallery on Start or your lock screen, you need to save it to your PC first.
Go to the Personalisation Gallery and tap or click Desktop backgrounds.
Once you've found the desktop background you want, tap or click the picture so it opens in your browser.
Press and hold or right-click the picture, then tap or click Save picture as.
Make sure that you're saving the picture in your Pictures library and tap or click Save. Then follow the steps to see the picture on the desktop, Start or the lock screen.
If you're using Internet Explorer 11, press and hold the picture and tap Save picture to save it to your Pictures library. (If you're using a mouse, right-click the picture and click on Save to pictures folder.)
Swipe in from the right edge of the screen, then tap Search.(If you're using a mouse, point to the top-right corner of the screen, move the mouse pointer down, then click Search.)
In the search box, enter desktop background, then tap or click Change desktop background.
Browse to the pictures you want to use. If you want only one desktop background picture, tap or click it to select it.
If you want to see a rotating slide show of pictures, select the checkboxes for the pictures you want to include in the slide show.
Tap or click Save changes.
You can set your desktop background picture as the background on your Start screen. Start will update automatically whenever the desktop background changes.
Open Taskbar and Navigation properties by swiping in from the right edge of the screen, tapping Search (or if you're using a mouse, pointing to the upper-right corner of the screen, moving the mouse pointer down, and then clicking Search), entering Taskbar in the search box, and then tapping or clicking Taskbar and Navigation in the results.
Tap or click the Navigation tab, then tap or click the Show my desktop background on Start checkbox to select it.
Tap or click OK.
You can choose just one favourite photo to use as a lock screen picture, or pick a few to create a lock screen slide show.
Swipe in from the right edge of the screen, tap Settings, then tap Change PC settings.(If you're using a mouse, point to the bottom-right corner of the screen, move the mouse pointer up, click Settings, then click Change PC settings.)
Tap or click PC and devices, then tap or click Lock screen.
If you want to use just one photo on your lock screen, tap or click Browse, then choose the picture you want (you can choose photos on your PC or SkyDrive).
Tap or click the picture you want to use to select it, then tap or click Choose Image.
To play a slide show on your lock screen, tap or click Play a slide show on the lock screen to turn it on.
Tap or click Add a folder and browse to the folder where you saved the pictures you want to use.
Tap or click the folder to select it, tap or click Choose this folder, then tap or click OK. You can pick up to ten folders.
By default, Windows will only use the pictures that fit on your screen best for the lock screen slide show. If you want to use all of the pictures in the folders you selected for your slide show, tap or click the Only use the pictures that will fit on my screen best slider to turn it off.