lately i'm having the problem that images with special characters in it's filenames are not displayed anymore. This definitely wasn't always like this.
As you can see here
there is no image displayed. The filenames include a german char "ä".
As this effects hundreds of posts i need to fix this.
In my research i came across "filename sanitizer" and "URL Encoding".
Sadly, i've no idea how to do that in the functions.php if that's even the right solution.
Any help would be very appreciated.