S3 URL switch to CF does not update in front end

I am using S3 to upload all my images, and have been using https://s3.amazonaws.com/~~~FOLDERNAME~~~/ this works fine, but now i have acticated CloundFront for that folder so resources are served more quickly. When I switch the web_path to https://dfzasdfryt6wsj6f.cloudfront.net, front end still loads images from old s3.amazonaws.com URL. I thought if I switched web_path, it will switch all images from new URL.

any clue why that is not happening.