Need help with initializng cropper (event.observe)

[nakins]

I'm trying to use David Spurr's Cropper JS within an aspx page. The problem I'm having is getting the cropper to attach to the image. I am uploading an image first to the server, then trying to crop. When my page, photo.aspx, first loads, a user can select/browser for an image to upload, and then upload it. The aspx page will turn around after the image has been written to a dir, and write a string to the page for the <img src ---- where the javascript for cropper can pick up the image and attach the cropper to it. But, I can't seem to get the cropper to attach. I believe it has to do with the "event.observe" method with attaches cropper to the image.

Event.observe( window, 'load', function() { CropImageManager.init(); } );

The page first loads without an image to crop. I think this is causing the Event.observe to load something that isn't there, if you know what I mean. Can someone suggest a different way to do this?