SVG (Scalable Vector Graphics) — according to specification on w3.org, is a language for describing vector and mixed vector-raster two-dimensional graphics, support animation and interactivity. SVG includes three types of objects: figures, images, and text.
SVG is underestimated by web-developers, although it has some important advantages. It is widely maintained by browsers, but there are some intricacies of using it in Internet Explorer and Opera, as well as everything does not go swimmingly in mobile applications.
Advantages of SVG
It looks perfectly on the retina. SVG does not lose in quality at scaling, there is no need to do multiple scalings.
Styling and scripting: using CSS you can change the graphics settings on the site. For example: background, transparency or borders.