Extended Search: disable showing .png Files

Describe the issue / Steps to reproduce:
Extended Search shows saved pictures / screenshots

Expected behavior:
Extended Search should only show pages as a search result.

Hello kaja.a,
you can exclude Namespaces from search, if you enter the following code in the config:

$GLOBALS['bsgESSourceConfig']['wikipage']['skip_namespaces'][] = NS_FILE;

In this example, you will no longer see any files in the search. You can also customize this code according to categories etc.