Remove all non-alphanumeric in file name images WordPress, add this code to functions.php

remove-all-non-alphanumeric.php

function wpartisan_sanitize_file_name( $filename ) { $sanitized_filename = remove_accents( $filename ); // Convert to ASCII 
$invalid = array( ' ' => '-', '%20' => '-', '_' => '-', ); 
$sanitized_filename = str_replace( array_keys( $invalid ), array_values( $invalid ), $sanitized_filename ); 
$sanitized_filename = preg_replace('/[^A-Za-z0-9-\. ]/', '', $sanitized_filename); // Remove all non-alphanumeric except . 
$sanitized_filename = preg_replace('/\.(?=.*\.)/', '', $sanitized_filename); // Remove all but last . 
$sanitized_filename = preg_replace('/-+/', '-', $sanitized_filename); // Replace any more than one - in a row 
$sanitized_filename = str_replace('-.', '.', $sanitized_filename); // Remove last - if at the end 
$sanitized_filename = strtolower( $sanitized_filename ); // Lowercase return $sanitized_filename;
}
add_filter( 'sanitize_file_name', 'wpartisan_sanitize_file_name', 10, 1 );