Image in confirmation mail

[vis18neu]

I tried to change the template for order confirmation mail in views/invoice/tmpl (invoice_items.php) for VM 2.0.6, because I want to show product thumbnails in that mail, but I cannot figure out the correct code to do so.
Whatever code I insert, I get little squares instead the images. I guess my image path is wrong. What is the correct code to show thumbnails in order mails?

[jenkinhill]

You will have to include the full url to the image files so they can be pulled from your site when the email is viewed by the customer.

[vis18neu]

Thank you, but it seems I'm still doing something wrong. Could you help me and tell me how should that code look like?

[jenkinhill]

I'm not a programmer - with this I know what needs to be done, but not how to do it.

[vis18neu]

Thank you