diff --git a/CONTRIBUTORS b/CONTRIBUTORS
index aa5a6d9..445b38d 100644
--- a/CONTRIBUTORS
+++ b/CONTRIBUTORS
@@ -14,3 +14,4 @@ Brendan Kenny <bckenny@google.com>
 Moisés Arcos <moiarcsan@gmail.com>
 Peter Grassberger <petertheone@gmail.com>
 Chris Fritz <us.chrisf@gmail.com>
+Jordan Schroter <jordan.schroter@gmail.com>
diff --git a/src/markerclusterer.js b/src/markerclusterer.js
index 554fcec..49cfe3d 100755
--- a/src/markerclusterer.js
+++ b/src/markerclusterer.js
@@ -245,8 +245,16 @@ MarkerClusterer.prototype.setupStyles_ = function() {
   }
 
   for (var i = 0, size; size = this.sizes[i]; i++) {
+    var url = '';
+
+    if (typeof this.imagePath_ === 'function') {
+      url = this.imagePath_(i, size);
+    } else {
+      url = this.imagePath_ + (i + 1) + '.' + this.imageExtension_;
+    }
+
     this.styles_.push({
-      url: this.imagePath_ + (i + 1) + '.' + this.imageExtension_,
+      url: url,
       height: size,
       width: size
     });