How to include images in templates phplist 3.3.1?

I have used an old phplist version for some years, but I guess it got obsolete, so a friend did the update for me to version 3.3.1.

I used to add lots of photos inserting the URLs into the templates.

In the new version this does not work anymore: the URLs of former sent messages are converted into weird codes which transform into pics in sent messages.

When I add an URL now it is not transformed into an image, but remains the URL address (text). And of course I have no clue to code anything else.

What format is the template file to upload? It takes JPEG but then the error is that the CONTENT placeholder is missing (although it is there).

Can somebody help please?
Thanks in advance!

@Schatzounette I don’t really understand what you mean. Can you show what the template looks like, either copy/paste or upload a file as an attachment.

I can only add text and can’t change the lay out in any way: the editor doesn’t work?
Thanks in advance

Hi, a friend of mine has finally installed the editor and I have got many option: I’m fighting my way through!
Thanks so much

@Schatzounette Yes, enabling the editor was what I was going to suggest.