1. A method, comprising: embedding a timer in an image located on a web server, wherein the timer embedded in the image is configured to continuously increment time as long as the image is hosted on the web server and the timer is configured to stop counting when the image is downloaded from the web server so that the downloaded image comprises an image-timer value embedded in the image indicating a time at which the image was downloaded from the web server; detecting, via a computing processor, that the image has been downloaded from the web server; determining, via a computing processor, the time at which the image was downloaded; sending to a database the time at which the image is downloaded from the web server; and using, via a computing processor, the time at which the image is downloaded from the web server to identify a device used to download the image from the web server.