Gravatar is developed by the same folks who created Wordpress. It is designed to provide a user with an avatar that can be used across a variety of websites. There is a video on the Gravatar home page that explains how it works.
In order to use a signature when composing an email in the GMail web interface, first create a Gravatar account for yourself using your countryschool.org email address.
I am going to give you instructions for uploading the Country School logo so that you will have a URL that you can use in creating your GMail signature. Once you have created your Gravatar account, follow the instructions below.
Grab this logo
Click to download the above file and save it to a location you can find later on.
Upload the logo to Gravatar
Grab the URL of the image location
Create your signature in GMail
You can also configure your Gravatar account to provide additional security by linking your account to your other social media.