To make sure that your SVG document that contains an image does not lose it, it is possible to include base64 versions of an image in the SVG document itself. There are a number of base64 converters around. Some add newlines at regular intervals which SVG accepts. Base64 encodes binary data by splitting the binary data into groups of 6 bits which are then converted into one of 64 character representations. Files tend to be about a third larger than the original size.
<image x="30" y="30" width="400" height="268" xlink:href="data:image/jpg;base64,/9j/4AAQSkZJRgABAQEASA......
Here is an example: