see bug 5560:
"You can include an image in an SVG, and if it is a raster image, you can
specify its size and position in the local (referring) SVG's coordinate system
and everything will scale just right no matter what size the actual PNG is. "
bug 5560 refers to <image> and many people will benefit from providing a similar facility for <use>.
Created attachment 1300 [details]
wheter using attachment or URL please view in recent firefox in fullscreen 1920x1080 for best results.
testcase dependencies include CSS animate, and transition
oops, please delete attachment