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In this artical we study about How we can upload .jfif file – get WordPress to support .jfif image upload- wp suport .jfif file use filter in function file
given below code us in theme function file for upload jfif file
add_filter( 'upload_mimes', 'custom_mime_types', 1, 1 );
function custom_mime_types( $mime_types ) {
$mime_types['jfif'] = 'image/jfif+xml'; // Adding .jfif extension
return $mime_types;
}