Actually i think it is GDM3 lockscreen
(ex. hxxp://1.bp.blogspot.com/-7k2I5TY3yuI/UJgzr2iar7I/AAAAAAAALmY/sJV0OHBWanI/s1600/gdm3.6-login-screen-background.png
Type: Posts; User: SPUTNLK
Actually i think it is GDM3 lockscreen
(ex. hxxp://1.bp.blogspot.com/-7k2I5TY3yuI/UJgzr2iar7I/AAAAAAAALmY/sJV0OHBWanI/s1600/gdm3.6-login-screen-background.png
is there anyway to change the default lockscreen to LightDM ??