You can use this Data-URL as image source. It will gzip better than base64-encoding the svg - containing already a base64-encoded image - again.
Big thanks go to Taylor Hunt for pointing out how to do this properly.
They're very easy to use: Take a look at this pen
you might notice that some JPGs, especially with large empty areas yield a lot of repetitions in the base64 code and you wonder why that is, because you always thought of JPG to be a highly compressed image format. But the JPGs the browser creates don't have optimized huffman tables (the option you can check in Photoshop "Save as Web" => "optimized")