[berkes]

Svg can, and often will, include (embed) raster images.

But even when not: in practice an SVG will have hundreds or thousands of XML elements (nodes) to draw rather simple-looking shapes even.

[GeoAtreides]

SVG often includes raster images? That's very surprising to me. I can see some use cases here and there, sure, but using a vector format to 'often' include raster images... i dunno.

Thousands of XML elements is the ideal case, compresses extremely well.

[squidbeak]

An example, many of Inkscape's filters depend on raster samples that need to be embedded. Complex gradients are also rasterised.

[vardump]

SVG can be rasterized into a cache and just blitted or composited as necessary.

No point to waste CPU cycles rasterizing same SVG image repeatedly.

[GeoAtreides]

One would assume the browser already renders the svgs once and the caches it. Maybe, who knows, probably depends on the browser.