Ftp links in img src, is it bad?

Question

HTML

Actually the question is, is it bad to insert direct links to FTP into img? If it's bad, then how to deal with it, what to google?
Oh yes, the web server and ftp server are on different machines.

Answer 1

Well, it's hard for you to raise http where is FTP? It's not hard and it's the easiest.

Answer 2

At a minimum, if you view the page via https, browsers will warn you that they are displaying insecure content.

Answer 3

Badly.
1) Not secure, anyone can intercept this data with access to the channel you are using.
2) Slowly. There is a transfer of many commands in both directions.