Can't get NPAPI plugin to work for mime-type "image/webp:webp:WebP"
===

I have compiled the NPAPI plugin for webP:

http://code.google.com/p/webp-npapi-linux/

It works great from my firefox. I simply do not understand how to get it to work from Google Chrome. I created the json file:

    $ cat manifest.json
    {
      "name": "My First Extension",
      "version": "1.0",
      "manifest_version": 2,
      "description": "The first extension that I made.",
      "plugins": [
        { "path": "webp-npapi.so", "public": true }
      ]
    }

I then start Google Chrome, go to chrome://extensions, click "Load unpacked extension...". I can see it appear in the list:

    My First Extension - Version: 1.0 (Unpacked)
    The first extension that I made.
    ID: bakhhdpebhmgoaecbmpkcbnmcmnamhhk

However I still cannot open no *.webp image !

What am I missing ?