Windows 8 comes with a nice feature in Lock Screen in which you can view notification and some other details even when your computer is locked. This feature is very useful if you are using Windows 8 on tablet.
If you wanna change Lock screen of your Windows 8 then you can change it from your User settings, but there are limited screen, if you are looking for more screens or wallpapers which you can apply to your Lock Screen then you can use LockPic.
LockPic is an freeware tool for your Windows 8, it comes with over 1000 screen which you can apply on your Lock screen. You can search for wallpapers and once you get it just open it and then click on Set As Lock Screen Image from bottom of the image.
The app is nice and time saving as you can perform search on the basis of category. Interface of app is also very nice and simple.