Hey Carl thanks for the reply.
I have had this problem now for ages, and only with Envato items. I’ve tweeted photos, videos, etc and it never seems to publish the embedded images. I do it from any other site, and its fine. The tweet I mentioned above is: https://twitter.com/thpstockphotos/status/664579864528224257
Could it have to do with removing the url that comes up when you click the Twitter button on the item and replacing it with the referral url instead?
May need some more investigating? Anyone else noticing the same issue?