Nokia Lumia 620 Lock screen bug?

[Keyren Kuraun]

Hi all^^ i'm new here, i have recently bought a lumia 620,but i noticed a strange thing,i can't change lock screen background , the screen remains all black,why? The changes are visibles only in the screen when i try to turn off device

 

[Rahul Rustagi]

Check in setting ease to acces switch off high contrast mode

 

[Keyren Kuraun]

oh god work ?_? trust me, i have try for weeks without resultxD it was so easy, thanks a lot *_*