What do you mean by returning it to the original? Are you not saving the resized photo under a new file name?
Do you have a Flickr or Photobucket account? If so you can just upload photos there, and then they put the image into several different sizes (original, large, medium, small, icon, etc.) and you can just get that image's URL (you can add photos to the gallery by URL as well as uploading from your own computer).