I don't know if this is a bug or what, but I at least noticed that in the demo ( http://eightmedia.github.io/yass.js/demo/ ) the "small" image gets loaded as well as the large one for me.. It's already started loading when the other thing starts downloading a new version. It would be nice not to incur extra requests for people - maybe the solution is to simply leave the src tag empty? Though that will break non-js websites.. There must be a better solution?