Examotion has a player that can display the image for svg files as a preview in Windows Explorer. Their product is free, but closed source. I believe that it also only works with files that actually end in .svg. I have a need for a similar product that works with files also ending in some other extensions.
Is there an OSS solution that could be modified to suit this need?
The mentioned examotion renesis player seems to be the only free explorer extension! It seems to be stable, has good reviews and is working for me (the tiger svg you posted is working as well - maybe that's a different problem with your system).
If support for further extensions is the only problem, I would simply patch your windows registry. Under
HKEY_CURRENT_USER\Software\Classes
there are entries for .svg and .svgz which declare to use the renesisplayer for thumbnail preview in explorer. you can simply add another key here like .mysvg similar to the existing keys.
Otherwise there are only commercial products like cadsofttools which has a svg plugin for irfanview and xnview.