SVG (Scalable Vector Graphics) is a novel file format for images. It uses XML and is based on vector graphics. The image file is basically a XML text document which you can edit in any word processor.
Converting the svg to png requires the Linux librsvg library and a line of PHP code:
$execCommand = "/usr/bin/rsvg-convert ".UPLOADPATH.$filename." --format=png -o ".UPLOADPATH.$filename.".png"
Some examples are given below.