It is very easy to create an image using the Azure gallery. Logon onto your Azure portal and select the new option under virtual machine. Using the from gallery option create an instance of Windows 2008. You will need to set the standard options like machine name and machine size.
Once your virtual machine is provisioned start it up and remote into. You will now need to install the Dynamics CRM email router and select and install 64 bit from it here and you will need to turn ie security off to download it
You will be prompted for install updates select yes
Once the email router is installed configure it to suit your requirements nd you and get the details here
A couple of things to note is that it may be worthwhile to copy the virtual machine VHD file locally so you can reuse elsewhere. Also if you are just playing around with this then be aware you may be incurring charges for processing and storage time. If you do delete your virtual machine make sure you also delete the storage i.e the underlying blob that holds the VHD.