Script uses an great online service http://labs.ideeinc.com/multicolr
to find similar images to path's fill color. Then it just replace the selected artwork with an image and clip it with the original path.
UPD: Seems like the idee services changing a lot. So, probably this script will stops works again in the feature. If it will happen, just post an comment here and I will try to fix it. Right now I do some hacks and upload new version of script, it works again. And its still get small previews from tineye hosting. I think it is possible to grab an original image from flickr, but it will work slower because of an additional server request and image file size.