Replace Seer

replaceseer.js

(function($) {
    
    var Memcache = function(hash) {
        var self = this,
        this.lookupCache = [],
        this.valueCache = [];

        $.map(hash, function(val, key) {
            self.lookupCache.push(key);
            self.valueCache.push(val);
        });
    };

    $.extend(Memcache.prototype, {
        lookup: function(key) {
            var result = this.lookupCache.indexOf(key);
            return (result !== -1) ? this.valueCache[result] : false;
        },
        identity: function(val) {
            return val;
        }
    });

    $.fn.replaceSeer = function(hashToProcess, options) {
        var store = new Memcache(hashToProcess)
          , defaults = { 
                liveUpdate: true,
                valueProcessor: Memcache.prototype.identity,
                keyProcessor: Memcache.prototype.identity,
            }
          , o = $.extend(defaults, options || (options = {}))
          , operator = !!$.fn.livequery && o.liveUpdate ? 'livequery' : 'each';

        return $(this)[operator](function() {
            var el = $(this)
              , src = o.valueProcessor(el.attr('src'))
              , replacement = store.lookup(o.keyProcessor(src));
            if (replacement) {
                el.attr('src', replacement);
            }
        });
    };

})(jQuery);

var options = {
    // keyProcessor: function(key) {
    //     return "http://someglobalpath.com/badImages/" + key;
    // },
    valueProcessor: function(val) {
        return "http://someglobalpath.com/images/" + val;
    }
};

// left side = image your want to replace,
// right side = image to replace it with
var replacementHash = {
    "imageToReplaceOne.jpg": "imageReplacementOne.png",
    "imageToReplaceTwo.jpg": "imageReplacementTwo.png",
    "imageToReplaceThree.jpg": "imageReplacementThree.png",
    "imageToReplaceFour.jpg": "imageReplacementFour.png"
};

$('img').replaceSeer(replacementHash, options);