Hi Hans,

In that case, you need to edit the template of the email:

Setting/technical/email/template/ ...

In the odoo v8 backend, each user can edit their own signature by clicking on their name (top left) | Preferences. [Administrators through: Settings | Users]

You need to host the images on a publically accessable space and then add the HTML code to suit your needs.  Here is an example but it can be whatever you like.

Hi Stephan,

thanks a lot for your help. 

It worked quite well for the e-mail. 

But if i use this in the signature it does not work. 

Any idea?