Sergex, SVG is an open image format. There are a few open source project like delineate to convert from other formats to svg. However, I don't know how it performs as I never used it. A very popular tool to make svg is inkscape.
As for using SVG in qt, refer QSvgRenderer and QSVGGraphicsItem. QSvgRenderer::load will load the image, say from a location or memory. QSvgGraphicsItem::setSharedrenderer(QSvgRenderer*) will then use that renderer. There are qt examples. Have a look at them too.