Go to your Control, then go to Email in the right sidebar, then System Emails. 

There you’ll find all the system emails that are sent out. When you click Edit you will get access to the HTML for the email. 

Find the image link for the logoipsum logo and replace it with a URL to your logo. 

Are there any specific image hosting pages that are recommended? I’ve tried Flickr and ImgBB urls and it works fine in test emails and in the preview but when it gets sent out there is no image in the email. The only thing I’ve changed from the template email is the url - which is a direct one to the image and the image sharing settings are public. Any suggestions?

There is a small trick that you can use to host the image on your community (as long as that community is not set to “private”):

Simply go into the editor and paste in / upload the image that you want to use. Then copy the url of this image, and add it to your email notification.

It does not require you to actually publish a topic or a reply with that image - simply uploading it into the editor will generate the url and it will work.

Thanks Julian! That solved the problem very easily.