It is working perfectly in every browser except ie8. ie8 shows no image only the alt tag text.
I disabled the picturefill script to see if that helped but that stopped it from working in firefox.
I’m not 100% clear on how your plugin is replacing the default worpdress img tags that are in the page/post with the srcset version but is there some type of “if” logic you could ad that if lower than ie9 then to just leave the default img tag in the page/post?
Not sure if that’s possible but seems like it could be?