A researcher disclosed a method of hiding up to three MB of data inside a Twitter image. The researcher showed both MP3 audio files and ZIP archives contained within the PNG images. The technique could be used by malware for facilitating its command-and-control C2 activities. The fact that the images can be hosted on a popular website like Twitter and are not sanitized opens up a possibility for their abuse by malicious actors. The PNG technique may not be particularly useful by itself as more steganography methods are viable.
Source: https://www.bleepingcomputer.com/news/security/twitter-images-can-be-abused-to-hide-zip-mp3-files-heres-how/