Spammers have created scores of bogus profiles and followed random users en masse. Each of the profiles comes has a sexy picture of a young woman, complete with a message from the spammer embedded inside the image. Spammers are putting their messages into the image because they know thats harder for Twitter to identify than if their adverts were presented in plaintext in a regular tweet. This is comparable to a trick weve seen email spammers use for some years. Read more in my article on the Naked Security website.”]
Source: https://grahamcluley.com/twitter-spammers-post-sexy-profile-pictures/