1. An image compression method, comprising: at an access server having one or more processors and memory for storing program modules to be executed by the one or more processors: receiving, by the access server, an image compression request submitted by a terminal, the image compression request comprising multiple to-be-compressed images or uniform resource locator (URL) addresses corresponding to the to-be-compressed images, and image compression time information corresponding to each of the to-be-compressed images; selecting, by the access server according to the image compression time information, a size of the to-be-compressed images and a target compression ratio, an image compression server whose load is lower than a preset threshold, and sending the image compression request to the selected image compression server, so that the selected image compression server can compress the images according to the image compression request and save the compressed images; receiving, by the access server, URL addresses of the compressed images from the selected image compression server; and forwarding, by the access server, the URL addresses of the compressed images to the terminal.