You two are mistaken.
Read the thread from the last time, I'm not mentioning about the GLOBAL Selector.
I left the image name with asterisk '*', it's what your image name you want to use. Within your first post, you used 'dark.png' for the tab. Then, I refers 'dark.png' with asterisk '*' or whatever if you have another one. There is no CSS declaration for the background with the value '*'. I showed you as just EXAMPLE.
Hope this help!