Use this awesome SVG thumbnail shell extension which works fine in Windows 7/8/10 (both 64-bit and 32-bit):
SVGSee - Extension module for Explorateur Windows to render SVG thumbnails, so that vous pouvez have an overview of your SVG files.
It is open source and free - what more can you ask for?
On Windows 10 after installing, try changing your SVG file association (the "Open With"). By changing it, something somehow gets refreshed, and it starts working.
