I am trying to create an email signature in outlook 2010 with the company logo embedded.

As i am working my way trough this, i find it very strange that the included image is sent as an attachment.

It doesn't show as attachment on Outlook from other users. But it does on Mac, hotmail and so on.. 

I have already tried to include it via HTML, thus placing the image on a FTP and loading it from there, and i have tried including it trough the signature editor, both won't make it work..
Is there a code to make this function?