Humming Via Kitchen

//  コレがデフォルト
$('a').asThumbnail();

//  引数でオプションを指定
$('a').asThumbnail({
    width: 100,
    height: 100
});

/**
 *  show element(s) as thumbnail
 *
 *  @author     Takanobu Izukawa
 *  @version    0.0.1
 */
jQuery.fn.extend({
    /**
     *  asThumbnail
     *
     *  @param options  Object that contains some parameter.
     *      width:          specified element width.
     *                      default value is 170px.
     *      height:         specified element height.
     *                      default value is 170px.
     *      pattern:        specified retrievable regex pattern.
     *                      default value is `abdeluxe` custom.
     *      replacement:    specified replace format.
     *                      default value is `abdeluxe` custom.
     *  @return         jQuery.
     */
    asThumbnail: function (options)
    {
        // fix options.
        options = options || {};
        //  declared default options.
        var defaultOptions = {
            'width': 170,
            'height': 170,
            'pattern': /^.*\/(\d+)\.html$/,
            'replacement': '/blog/entryimg/$1.jpg'
        };
        //  merge options.
        options = jQuery.extend({}, defaultOptions, options);
        //  execute effect to each element(s).
        return this.filter('a')
        .each(function()
        {
            //  retrieve image url.
            var imageURL = this.href.replace(options.pattern,
                                             options.replacement);
            //  attach new css.
            jQuery(this).css({
                'display': 'block',
                'width': options.width + 'px',      //  should be width method instead?
                'height': options.height + 'px',    //  should be height method instead?
                'background-image': 'url(' + imageURL + ')',
                'background-repeat': 'no-repeat',
                'background-position': '50% 50%'
            }).empty();
        }).end();
    }
});