File icon disappears after new installation

try setting $wgServer explicitly in your LocalSettings.php

If all else fails you can try setting $wgStylePath also in LocalSettings.php, but generally that variable is automatically set based on $wgServer and $wgScriptPath, and if $wgServer is wrong, several other variables will be wrong (often causing symptoms like http redirects (like when saving a page or doing ?action=purge ) not working)