First of all you would need to upload the image either on your hosting account or on an image-sharing site.

In order to add an image to your signature in RoundCube you will be required to:

1. Log into Roundcube at http://www.yourdomain.com/webmail/ (replace yourdomain.com with your domain name).
2. Select Settings on the top right hand corner.
3. Select Identities.
4. Find and click on the desired identity in the left hand panel.
5. Select the HTML signature tick box.
6. Select the HTML icon in the WYSIWYG (What you see is what you get) editor.
7. Insert the following line of HTML:
   • <img src="http://help.webserver.com.my/images/logo.png">
   • make sure you replace the link above with a link to your own logo.
8. Select Save.
9. Select Preferences in the left hand menu.
10. Select Composing Messages.
11. Change Compose HTML messages to always.
12. Select Save.

Your signature will now have a copy of your logo upon composing a new message within Roundcube.