After being a little disappointed at the lack of image integration support in the signature/disclaimer configuration on my exchange 2013 environment I investigated other options such as base64 image integration.
Sadly there is 5000 character limit which pretty much leaves very little space for a decent image/logo on the signature which is applied.
Naturally placing a http URL in the email signature does not work since Outlook and many other email clients wont download the file as it may not be trusted.
This came as a slight surprise but it works:
Use an HTTPS Url for your signature image.
Below is an example of the signature I created:
Below is a piece of it taken from my Hotmail account, after stripping out all the company info there is not much left, but I am you can get the idea:
* UPDATE *
Sadly this will not work as a signature. REASON: The disclaimer function stamps every single email for the users included in this rule, resulting in multiple’s of these being stamped at the bottom of the emails.