I am trying to send a HTML mail from php that contains an image. 

I receive the email and all the HTML tags look good except for the `<img>` tag.

The message of the email looks like this:

`$message = '<img src="http://your-click.ch/wp-content/uploads/2014/11/logo1.png" alt="Your Click" width="131" height="52" border="0" />';`

When I receive the mail, I see that there is an image but it is just blank. When I check the element, I see this code:

```
<img alt="Your Click" width="131" height="52" border="0">

```

As you see the whole src attribute is missing? Why?