Assuming artifacts and unnatural elements do not exist in the media in question and that the media is indistinguishable to the human eye, the only way to be able to do this is to trace back to the source of the images.
An analogy can be drawn to DoS (Denial of Service) attack, where an absurd number of requests are sent from a single IP to a single server causing it to crash - A common solution is a honeypot, where a high number of requests from one IP is redirected to a decoy server where, even if it crashes, uptime is not compromised. Some research has been done on these lines where this paper spoke about verifying the digital signature of an image or this one where they proposed tampered image detection and source camera identification.
Once traced back to a source, if an absurd number of potentially fake images come from a singular source, it is to be questioned.
The common fear arises when we are dealing with something, on the basis of the analogy, like a DDoS (Distributed Denial of Service) attack where each fake request comes from a distributed source - Network Security has found ways to deal with this, but security and fraud detection in the terms of AI just isn't that established.
Essentially for a well thought out artificial media for a specific malicious purpose, today, is quite hard to be caught - But work is being done currently on security in AI. If you're planning on using artificial media for malicious purposes, I'd say now is the best time probably.
This security has been a concern from a bit now. An article written by a data scientist quotes
Deepfakes have already been used to try to harass and humiliate women through fake porn videos. The term actually comes from the username of a Reddit user who was creating these videos by building generative adversarial networks (GANs) using TensorFlow. Now, intelligence officials are talking about the possibility of Vladimir Putin using fake videos to influence the 2020 presidential elections. More research is being done on deepfakes as a threat to democracy and national security, as well as how to detect them.
Note - I'm quite clueless about network security, all my knowledge comes from one conversation with a friend, and thought this would be a good analogy to use here. Forgive any errors in the analogy and please correct if possible!