How to add portrait when encounter this...

Ｉ found that I can insert every player portraits correctly by changing the portrait`s name (ID) consistent with the ID shown in the game. But portraits can NOT be displayed whenever there is a　grey silhouette names `NO IMAGE AVAILABLE`. How can I replace my portrait with this??

I tried to add the portrait by add sth like
but there is still no change...

It´s a default image of your skin... Go to your skin folder, then to graphics, then to pictures and delete the folder with that image.