As the name implies, vector drawables are based on vector graphics. Vector graphics are a way of describing graphical elements using geometric shapes. This lets you create a drawable based on an XML vector graphic. Now there is no need to design different size image for mdpi, hdpi, xhdpi and etc. With Vector Drawable you need to create image only once as an xml file and you can scale it for all dpi and for different devices. This also not save space but also simplifies maintenance.