Where to store Icon for "xv"

["Edward C. Jones" <edcjones@comcast.net>]

I use up-to-date debian testing (wheezy), amd64 version, with kde.

I have just compiled and installed the old image viewer "xv".  In stable 
(squeeze), there is an icon for xv that can be put on the panel. For 
testing (wheezy), the system could not find an xv icon, so I installed a 
blank icon.  But an icon appears to exist in 
/usr/share/icons/mono/scalable/apps/xv.svgz.

The process for changing a application icon on the panel appears to be:
   Right click on the old icon
   Click Icon Settings
   Click on the spot where the icon should be (upper left of Icon 
Settings window)
   Choose new icon.
Where do I put xv.svgz (or any icon I download) so this process can find it?