Efficient delivery of animated image files

A method of delivering animated images by an edge server to a web browser is disclosed. The method includes receiving a request for an image file. It includes detecting the image file as an animated image file. It includes generating two or more versions of the animated image file, including a first version of the animated image file having at least some frames at lower-resolution than corresponding frames in the animated image file, and including a second version of the animated image file having at least some frames at higher-resolution than corresponding frames in the first version of the animated image file. It includes sending the first version of the animated image file in response to the request for the image file and delaying delivery of the second version of the animated image file until a subsequent request for the second version of animated image file is received.