You shouldn’t use ftp address.
You should use .
Because the picture is in the same directory as your index/html file, you can just put the file name.
If your picture was in a folder called images and your index file stays where it is, you use
If your picture was in images and your index file in documents, you would use . The …/ makes it down ‘down’ a directory.
And you put your files in that darkerkind.com directory.
Just been to your site and you’ve put the index file in the right place so it’s just the image